diff --git a/packages/react-native/Libraries/Core/setUpReactDevTools.js b/packages/react-native/Libraries/Core/setUpReactDevTools.js
index e25f0a44c98073..7bbc209a7e2653 100644
--- a/packages/react-native/Libraries/Core/setUpReactDevTools.js
+++ b/packages/react-native/Libraries/Core/setUpReactDevTools.js
@@ -1,261 +1,261 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @flow
- * @format
- */
+// /**
+//  * Copyright (c) Meta Platforms, Inc. and affiliates.
+//  *
+//  * This source code is licensed under the MIT license found in the
+//  * LICENSE file in the root directory of this source tree.
+//  *
+//  * @flow
+//  * @format
+//  */
 
-'use strict';
+// 'use strict';
 
-import type {Domain} from '../../src/private/devsupport/rndevtools/setUpFuseboxReactDevToolsDispatcher';
-import type {Spec as NativeReactDevToolsRuntimeSettingsModuleSpec} from '../../src/private/devsupport/rndevtools/specs/NativeReactDevToolsRuntimeSettingsModule';
+// import type {Domain} from '../../src/private/devsupport/rndevtools/setUpFuseboxReactDevToolsDispatcher';
+// import type {Spec as NativeReactDevToolsRuntimeSettingsModuleSpec} from '../../src/private/devsupport/rndevtools/specs/NativeReactDevToolsRuntimeSettingsModule';
 
-if (__DEV__) {
-  if (typeof global.queueMicrotask !== 'function') {
-    console.error(
-      'queueMicrotask should exist before setting up React DevTools.',
-    );
-  }
+// if (__DEV__) {
+//   if (typeof global.queueMicrotask !== 'function') {
+//     console.error(
+//       'queueMicrotask should exist before setting up React DevTools.',
+//     );
+//   }
 
-  // Keep in sync with ExceptionsManager/installConsoleErrorReporter
-  // $FlowExpectedError[prop-missing]
-  if (console._errorOriginal != null) {
-    console.error(
-      'ExceptionsManager should be set up after React DevTools to avoid console.error arguments mutation',
-    );
-  }
-}
+//   // Keep in sync with ExceptionsManager/installConsoleErrorReporter
+//   // $FlowExpectedError[prop-missing]
+//   if (console._errorOriginal != null) {
+//     console.error(
+//       'ExceptionsManager should be set up after React DevTools to avoid console.error arguments mutation',
+//     );
+//   }
+// }
 
-if (__DEV__) {
-  // Register dispatcher on global, which can be used later by Chrome DevTools frontend
-  require('../../src/private/devsupport/rndevtools/setUpFuseboxReactDevToolsDispatcher');
-  const {
-    initialize,
-    connectToDevTools,
-    connectWithCustomMessagingProtocol,
-  } = require('react-devtools-core');
+// if (__DEV__) {
+//   // Register dispatcher on global, which can be used later by Chrome DevTools frontend
+//   require('../../src/private/devsupport/rndevtools/setUpFuseboxReactDevToolsDispatcher');
+//   const {
+//     initialize,
+//     connectToDevTools,
+//     connectWithCustomMessagingProtocol,
+//   } = require('react-devtools-core');
 
-  const reactDevToolsSettingsManager = require('../../src/private/devsupport/rndevtools/ReactDevToolsSettingsManager');
-  const serializedHookSettings =
-    reactDevToolsSettingsManager.getGlobalHookSettings();
-  const maybeReactDevToolsRuntimeSettingsModuleModule =
-    require('../../src/private/devsupport/rndevtools/specs/NativeReactDevToolsRuntimeSettingsModule').default;
+//   const reactDevToolsSettingsManager = require('../../src/private/devsupport/rndevtools/ReactDevToolsSettingsManager');
+//   const serializedHookSettings =
+//     reactDevToolsSettingsManager.getGlobalHookSettings();
+//   const maybeReactDevToolsRuntimeSettingsModuleModule =
+//     require('../../src/private/devsupport/rndevtools/specs/NativeReactDevToolsRuntimeSettingsModule').default;
 
-  let hookSettings = null;
-  if (serializedHookSettings != null) {
-    try {
-      const parsedSettings = JSON.parse(serializedHookSettings);
-      hookSettings = parsedSettings;
-    } catch {
-      console.error(
-        'Failed to parse persisted React DevTools hook settings. React DevTools will be initialized with default settings.',
-      );
-    }
-  }
+//   let hookSettings = null;
+//   if (serializedHookSettings != null) {
+//     try {
+//       const parsedSettings = JSON.parse(serializedHookSettings);
+//       hookSettings = parsedSettings;
+//     } catch {
+//       console.error(
+//         'Failed to parse persisted React DevTools hook settings. React DevTools will be initialized with default settings.',
+//       );
+//     }
+//   }
 
-  const {
-    isProfiling: shouldStartProfilingNow,
-    profilingSettings: initialProfilingSettings,
-  } = readReloadAndProfileConfig(maybeReactDevToolsRuntimeSettingsModuleModule);
+//   const {
+//     isProfiling: shouldStartProfilingNow,
+//     profilingSettings: initialProfilingSettings,
+//   } = readReloadAndProfileConfig(maybeReactDevToolsRuntimeSettingsModuleModule);
 
-  // Install hook before React is loaded.
-  initialize(hookSettings, shouldStartProfilingNow, initialProfilingSettings);
+//   // Install hook before React is loaded.
+//   initialize(hookSettings, shouldStartProfilingNow, initialProfilingSettings);
 
-  // This should be defined in DEV, otherwise error is expected.
-  const fuseboxReactDevToolsDispatcher =
-    global.__FUSEBOX_REACT_DEVTOOLS_DISPATCHER__;
-  const reactDevToolsFuseboxGlobalBindingName =
-    fuseboxReactDevToolsDispatcher.BINDING_NAME;
+//   // This should be defined in DEV, otherwise error is expected.
+//   const fuseboxReactDevToolsDispatcher =
+//     global.__FUSEBOX_REACT_DEVTOOLS_DISPATCHER__;
+//   const reactDevToolsFuseboxGlobalBindingName =
+//     fuseboxReactDevToolsDispatcher.BINDING_NAME;
 
-  const ReactNativeStyleAttributes =
-    require('../Components/View/ReactNativeStyleAttributes').default;
-  const resolveRNStyle = require('../StyleSheet/flattenStyle').default;
+//   const ReactNativeStyleAttributes =
+//     require('../Components/View/ReactNativeStyleAttributes').default;
+//   const resolveRNStyle = require('../StyleSheet/flattenStyle').default;
 
-  function handleReactDevToolsSettingsUpdate(settings: Object) {
-    reactDevToolsSettingsManager.setGlobalHookSettings(
-      JSON.stringify(settings),
-    );
-  }
+//   function handleReactDevToolsSettingsUpdate(settings: Object) {
+//     reactDevToolsSettingsManager.setGlobalHookSettings(
+//       JSON.stringify(settings),
+//     );
+//   }
 
-  let disconnect = null;
-  function disconnectBackendFromReactDevToolsInFuseboxIfNeeded() {
-    if (disconnect != null) {
-      disconnect();
-      disconnect = null;
-    }
-  }
+//   let disconnect = null;
+//   function disconnectBackendFromReactDevToolsInFuseboxIfNeeded() {
+//     if (disconnect != null) {
+//       disconnect();
+//       disconnect = null;
+//     }
+//   }
 
-  function connectToReactDevToolsInFusebox(domain: Domain) {
-    const {
-      isReloadAndProfileSupported,
-      isProfiling,
-      onReloadAndProfile,
-      onReloadAndProfileFlagsReset,
-    } = readReloadAndProfileConfig(
-      maybeReactDevToolsRuntimeSettingsModuleModule,
-    );
-    disconnect = connectWithCustomMessagingProtocol({
-      onSubscribe: listener => {
-        domain.onMessage.addEventListener(listener);
-      },
-      onUnsubscribe: listener => {
-        domain.onMessage.removeEventListener(listener);
-      },
-      onMessage: (event, payload) => {
-        domain.sendMessage({event, payload});
-      },
-      nativeStyleEditorValidAttributes: Object.keys(ReactNativeStyleAttributes),
-      resolveRNStyle,
-      onSettingsUpdated: handleReactDevToolsSettingsUpdate,
-      isReloadAndProfileSupported,
-      isProfiling,
-      onReloadAndProfile,
-      onReloadAndProfileFlagsReset,
-    });
-  }
+//   function connectToReactDevToolsInFusebox(domain: Domain) {
+//     const {
+//       isReloadAndProfileSupported,
+//       isProfiling,
+//       onReloadAndProfile,
+//       onReloadAndProfileFlagsReset,
+//     } = readReloadAndProfileConfig(
+//       maybeReactDevToolsRuntimeSettingsModuleModule,
+//     );
+//     disconnect = connectWithCustomMessagingProtocol({
+//       onSubscribe: listener => {
+//         domain.onMessage.addEventListener(listener);
+//       },
+//       onUnsubscribe: listener => {
+//         domain.onMessage.removeEventListener(listener);
+//       },
+//       onMessage: (event, payload) => {
+//         domain.sendMessage({event, payload});
+//       },
+//       nativeStyleEditorValidAttributes: Object.keys(ReactNativeStyleAttributes),
+//       resolveRNStyle,
+//       onSettingsUpdated: handleReactDevToolsSettingsUpdate,
+//       isReloadAndProfileSupported,
+//       isProfiling,
+//       onReloadAndProfile,
+//       onReloadAndProfileFlagsReset,
+//     });
+//   }
 
-  let isWebSocketOpen = false;
-  let ws = null;
-  function connectToWSBasedReactDevToolsFrontend() {
-    if (ws !== null && isWebSocketOpen) {
-      // If the DevTools backend is already connected, don't recreate the WebSocket.
-      // This would break the connection.
-      // If there isn't an active connection, a backend may be waiting to connect,
-      // in which case it's okay to make a new one.
-      return;
-    }
+//   let isWebSocketOpen = false;
+//   let ws = null;
+//   function connectToWSBasedReactDevToolsFrontend() {
+//     if (ws !== null && isWebSocketOpen) {
+//       // If the DevTools backend is already connected, don't recreate the WebSocket.
+//       // This would break the connection.
+//       // If there isn't an active connection, a backend may be waiting to connect,
+//       // in which case it's okay to make a new one.
+//       return;
+//     }
 
-    // not when debugging in chrome
-    // TODO(t12832058) This check is broken
-    if (!window.document) {
-      const AppState = require('../AppState/AppState').default;
-      const getDevServer = require('./Devtools/getDevServer').default;
+//     // not when debugging in chrome
+//     // TODO(t12832058) This check is broken
+//     if (!window.document) {
+//       const AppState = require('../AppState/AppState').default;
+//       const getDevServer = require('./Devtools/getDevServer').default;
 
-      // Don't steal the DevTools from currently active app.
-      // Note: if you add any AppState subscriptions to this file,
-      // you will also need to guard against `AppState.isAvailable`,
-      // or the code will throw for bundles that don't have it.
-      const isAppActive = () => AppState.currentState !== 'background';
+//       // Don't steal the DevTools from currently active app.
+//       // Note: if you add any AppState subscriptions to this file,
+//       // you will also need to guard against `AppState.isAvailable`,
+//       // or the code will throw for bundles that don't have it.
+//       const isAppActive = () => AppState.currentState !== 'background';
 
-      // Get hostname from development server (packager)
-      const devServer = getDevServer();
-      const host = devServer.bundleLoadedFromServer
-        ? devServer.url
-            .replace(/https?:\/\//, '')
-            .replace(/\/$/, '')
-            .split(':')[0]
-        : 'localhost';
+//       // Get hostname from development server (packager)
+//       const devServer = getDevServer();
+//       const host = devServer.bundleLoadedFromServer
+//         ? devServer.url
+//             .replace(/https?:\/\//, '')
+//             .replace(/\/$/, '')
+//             .split(':')[0]
+//         : 'localhost';
 
-      // Read the optional global variable for backward compatibility.
-      // It was added in https://github.com/facebook/react-native/commit/bf2b435322e89d0aeee8792b1c6e04656c2719a0.
-      const port =
-        // $FlowFixMe[prop-missing]
-        // $FlowFixMe[incompatible-use]
-        window.__REACT_DEVTOOLS_PORT__ != null
-          ? window.__REACT_DEVTOOLS_PORT__
-          : 8097;
+//       // Read the optional global variable for backward compatibility.
+//       // It was added in https://github.com/facebook/react-native/commit/bf2b435322e89d0aeee8792b1c6e04656c2719a0.
+//       const port =
+//         // $FlowFixMe[prop-missing]
+//         // $FlowFixMe[incompatible-use]
+//         window.__REACT_DEVTOOLS_PORT__ != null
+//           ? window.__REACT_DEVTOOLS_PORT__
+//           : 8097;
 
-      const WebSocket = require('../WebSocket/WebSocket').default;
-      ws = new WebSocket('ws://' + host + ':' + port);
-      ws.addEventListener('close', event => {
-        isWebSocketOpen = false;
-      });
-      ws.addEventListener('open', event => {
-        isWebSocketOpen = true;
-      });
+//       const WebSocket = require('../WebSocket/WebSocket').default;
+//       ws = new WebSocket('ws://' + host + ':' + port);
+//       ws.addEventListener('close', event => {
+//         isWebSocketOpen = false;
+//       });
+//       ws.addEventListener('open', event => {
+//         isWebSocketOpen = true;
+//       });
 
-      const {
-        isReloadAndProfileSupported,
-        isProfiling,
-        onReloadAndProfile,
-        onReloadAndProfileFlagsReset,
-      } = readReloadAndProfileConfig(
-        maybeReactDevToolsRuntimeSettingsModuleModule,
-      );
-      connectToDevTools({
-        isAppActive,
-        resolveRNStyle,
-        nativeStyleEditorValidAttributes: Object.keys(
-          ReactNativeStyleAttributes,
-        ),
-        websocket: ws,
-        onSettingsUpdated: handleReactDevToolsSettingsUpdate,
-        isReloadAndProfileSupported,
-        isProfiling,
-        onReloadAndProfile,
-        onReloadAndProfileFlagsReset,
-      });
-    }
-  }
+//       const {
+//         isReloadAndProfileSupported,
+//         isProfiling,
+//         onReloadAndProfile,
+//         onReloadAndProfileFlagsReset,
+//       } = readReloadAndProfileConfig(
+//         maybeReactDevToolsRuntimeSettingsModuleModule,
+//       );
+//       connectToDevTools({
+//         isAppActive,
+//         resolveRNStyle,
+//         nativeStyleEditorValidAttributes: Object.keys(
+//           ReactNativeStyleAttributes,
+//         ),
+//         websocket: ws,
+//         onSettingsUpdated: handleReactDevToolsSettingsUpdate,
+//         isReloadAndProfileSupported,
+//         isProfiling,
+//         onReloadAndProfile,
+//         onReloadAndProfileFlagsReset,
+//       });
+//     }
+//   }
 
-  // 1. If React DevTools has already been opened and initialized in Fusebox, bindings survive reloads
-  if (global[reactDevToolsFuseboxGlobalBindingName] != null) {
-    disconnectBackendFromReactDevToolsInFuseboxIfNeeded();
-    const domain =
-      fuseboxReactDevToolsDispatcher.initializeDomain('react-devtools');
-    connectToReactDevToolsInFusebox(domain);
-  }
+//   // 1. If React DevTools has already been opened and initialized in Fusebox, bindings survive reloads
+//   if (global[reactDevToolsFuseboxGlobalBindingName] != null) {
+//     disconnectBackendFromReactDevToolsInFuseboxIfNeeded();
+//     const domain =
+//       fuseboxReactDevToolsDispatcher.initializeDomain('react-devtools');
+//     connectToReactDevToolsInFusebox(domain);
+//   }
 
-  // 2. If React DevTools panel in Fusebox was opened for the first time after the runtime has been created
-  // 2. OR if React DevTools frontend was re-initialized: Chrome DevTools was closed and then re-opened
-  global.__FUSEBOX_REACT_DEVTOOLS_DISPATCHER__.onDomainInitialization.addEventListener(
-    (domain: Domain) => {
-      if (domain.name === 'react-devtools') {
-        disconnectBackendFromReactDevToolsInFuseboxIfNeeded();
-        connectToReactDevToolsInFusebox(domain);
-      }
-    },
-  );
+//   // 2. If React DevTools panel in Fusebox was opened for the first time after the runtime has been created
+//   // 2. OR if React DevTools frontend was re-initialized: Chrome DevTools was closed and then re-opened
+//   global.__FUSEBOX_REACT_DEVTOOLS_DISPATCHER__.onDomainInitialization.addEventListener(
+//     (domain: Domain) => {
+//       if (domain.name === 'react-devtools') {
+//         disconnectBackendFromReactDevToolsInFuseboxIfNeeded();
+//         connectToReactDevToolsInFusebox(domain);
+//       }
+//     },
+//   );
 
-  // 3. Fallback to attempting to connect WS-based RDT frontend
-  const RCTNativeAppEventEmitter =
-    require('../EventEmitter/RCTNativeAppEventEmitter').default;
-  RCTNativeAppEventEmitter.addListener(
-    'RCTDevMenuShown',
-    connectToWSBasedReactDevToolsFrontend,
-  );
-  connectToWSBasedReactDevToolsFrontend(); // Try connecting once on load
-}
+//   // 3. Fallback to attempting to connect WS-based RDT frontend
+//   const RCTNativeAppEventEmitter =
+//     require('../EventEmitter/RCTNativeAppEventEmitter').default;
+//   RCTNativeAppEventEmitter.addListener(
+//     'RCTDevMenuShown',
+//     connectToWSBasedReactDevToolsFrontend,
+//   );
+//   connectToWSBasedReactDevToolsFrontend(); // Try connecting once on load
+// }
 
-function readReloadAndProfileConfig(
-  maybeModule: ?NativeReactDevToolsRuntimeSettingsModuleSpec,
-) {
-  const isReloadAndProfileSupported = maybeModule != null;
-  const config = maybeModule?.getReloadAndProfileConfig();
-  const isProfiling = config?.shouldReloadAndProfile === true;
-  const profilingSettings = {
-    recordChangeDescriptions: config?.recordChangeDescriptions === true,
-    recordTimeline: false,
-  };
-  const onReloadAndProfile = (recordChangeDescriptions: boolean) => {
-    if (maybeModule == null) {
-      return;
-    }
+// function readReloadAndProfileConfig(
+//   maybeModule: ?NativeReactDevToolsRuntimeSettingsModuleSpec,
+// ) {
+//   const isReloadAndProfileSupported = maybeModule != null;
+//   const config = maybeModule?.getReloadAndProfileConfig();
+//   const isProfiling = config?.shouldReloadAndProfile === true;
+//   const profilingSettings = {
+//     recordChangeDescriptions: config?.recordChangeDescriptions === true,
+//     recordTimeline: false,
+//   };
+//   const onReloadAndProfile = (recordChangeDescriptions: boolean) => {
+//     if (maybeModule == null) {
+//       return;
+//     }
 
-    maybeModule.setReloadAndProfileConfig({
-      shouldReloadAndProfile: true,
-      recordChangeDescriptions,
-    });
-  };
-  const onReloadAndProfileFlagsReset = () => {
-    if (maybeModule == null) {
-      return;
-    }
+//     maybeModule.setReloadAndProfileConfig({
+//       shouldReloadAndProfile: true,
+//       recordChangeDescriptions,
+//     });
+//   };
+//   const onReloadAndProfileFlagsReset = () => {
+//     if (maybeModule == null) {
+//       return;
+//     }
 
-    maybeModule.setReloadAndProfileConfig({
-      shouldReloadAndProfile: false,
-      recordChangeDescriptions: false,
-    });
-  };
+//     maybeModule.setReloadAndProfileConfig({
+//       shouldReloadAndProfile: false,
+//       recordChangeDescriptions: false,
+//     });
+//   };
 
-  return {
-    isReloadAndProfileSupported,
-    isProfiling,
-    profilingSettings,
-    onReloadAndProfile,
-    onReloadAndProfileFlagsReset,
-  };
-}
+//   return {
+//     isReloadAndProfileSupported,
+//     isProfiling,
+//     profilingSettings,
+//     onReloadAndProfile,
+//     onReloadAndProfileFlagsReset,
+//   };
+// }
diff --git a/packages/react-native/Libraries/ReactNative/FabricUIManager.js b/packages/react-native/Libraries/ReactNative/FabricUIManager.js
index 13b203f0abd953..4494f07a61252b 100644
--- a/packages/react-native/Libraries/ReactNative/FabricUIManager.js
+++ b/packages/react-native/Libraries/ReactNative/FabricUIManager.js
@@ -27,6 +27,7 @@ import defineLazyObjectProperty from '../Utilities/defineLazyObjectProperty';
 
 export type NodeSet = Array<Node>;
 export type NodeProps = {...};
+export opaque type ShadowNodeFamilyReference = mixed;
 export interface Spec {
   +createNode: (
     reactTag: number,
@@ -40,6 +41,7 @@ export interface Spec {
   +cloneNodeWithNewProps: (node: Node, newProps: NodeProps) => Node;
   +cloneNodeWithNewChildrenAndProps: (node: Node, newProps: NodeProps) => Node;
   +createChildSet: (rootTag: RootTag) => NodeSet;
+  +createShadowNodeFamilyReference: (node: Node) => ShadowNodeFamilyReference;
   +appendChild: (parentNode: Node, child: Node) => Node;
   +appendChildToSet: (childSet: NodeSet, child: Node) => void;
   +completeRoot: (rootTag: RootTag, childSet: NodeSet) => void;
@@ -111,6 +113,7 @@ const CACHED_PROPERTIES = [
   'cloneNodeWithNewProps',
   'cloneNodeWithNewChildrenAndProps',
   'createChildSet',
+  'createShadowNodeFamilyReference',
   'appendChild',
   'appendChildToSet',
   'completeRoot',
diff --git a/packages/react-native/React/Base/RCTBundleURLProvider.mm b/packages/react-native/React/Base/RCTBundleURLProvider.mm
index fb1d601c075d8d..9feb42e2d4e7c1 100644
--- a/packages/react-native/React/Base/RCTBundleURLProvider.mm
+++ b/packages/react-native/React/Base/RCTBundleURLProvider.mm
@@ -388,7 +388,7 @@ - (void)updateValue:(id)object forKey:(NSString *)key
 
 - (BOOL)enableDev
 {
-  return [[NSUserDefaults standardUserDefaults] boolForKey:kRCTEnableDevKey];
+  return NO;
 }
 
 - (BOOL)enableMinification
diff --git a/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.cpp b/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.cpp
index 3ec219424f3eb2..5c6055aec03cff 100644
--- a/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.cpp
+++ b/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.cpp
@@ -1,3 +1,4 @@
+
 /*
  * Copyright (c) Meta Platforms, Inc. and affiliates.
  *
@@ -128,6 +129,26 @@ void TurboModuleBinding::install(
     return;
   }
 
+  defineReadOnlyGlobal(
+      runtime,
+      "RN$clearLongLivedObjectCollection",
+      jsi::Function::createFromHostFunction(
+          runtime,
+          jsi::PropNameID::forAscii(
+              runtime, "RN$clearLongLivedObjectCollection"),
+          0,
+          [longLivedObjectCollection](
+              jsi::Runtime& rt,
+              const jsi::Value& /*thisVal*/,
+              const jsi::Value* /*args*/,
+              size_t /*count*/) {
+            LongLivedObjectCollection::get(rt).clear();
+            if (longLivedObjectCollection) {
+              longLivedObjectCollection->clear();
+            }
+            return jsi::Value::undefined();
+          }));
+
   defineReadOnlyGlobal(runtime, "RN$UnifiedNativeModuleProxy", true);
   defineReadOnlyGlobal(
       runtime,
diff --git a/packages/react-native/ReactCommon/react/nativemodule/intersectionobserver/NativeIntersectionObserver.cpp b/packages/react-native/ReactCommon/react/nativemodule/intersectionobserver/NativeIntersectionObserver.cpp
index 531d9ae416e34b..91b441e4b5ed4a 100644
--- a/packages/react-native/ReactCommon/react/nativemodule/intersectionobserver/NativeIntersectionObserver.cpp
+++ b/packages/react-native/ReactCommon/react/nativemodule/intersectionobserver/NativeIntersectionObserver.cpp
@@ -37,7 +37,7 @@ void NativeIntersectionObserver::observe(
 
   intersectionObserverManager_.observe(
       intersectionObserverId,
-      shadowNode,
+      shadowNode->getFamilyShared(),
       thresholds,
       rootThresholds,
       uiManager);
@@ -48,7 +48,8 @@ void NativeIntersectionObserver::unobserve(
     IntersectionObserverObserverId intersectionObserverId,
     jsi::Object targetShadowNode) {
   auto shadowNode = shadowNodeFromValue(runtime, std::move(targetShadowNode));
-  intersectionObserverManager_.unobserve(intersectionObserverId, *shadowNode);
+  intersectionObserverManager_.unobserve(
+      intersectionObserverId, shadowNode->getFamilyShared());
 }
 
 void NativeIntersectionObserver::connect(
@@ -101,7 +102,7 @@ NativeIntersectionObserver::convertToNativeModuleEntry(
 
   NativeIntersectionObserverEntry nativeModuleEntry = {
       entry.intersectionObserverId,
-      (*entry.shadowNode).getInstanceHandle(runtime),
+      (*entry.shadowNodeFamily).getInstanceHandle(runtime),
       targetRect,
       rootRect,
       intersectionRect,
diff --git a/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp b/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp
index 3af382c1dd6403..8bda5b733d0a72 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp
@@ -191,12 +191,7 @@ const SharedEventEmitter& ShadowNode::getEventEmitter() const {
 }
 
 jsi::Value ShadowNode::getInstanceHandle(jsi::Runtime& runtime) const {
-  auto instanceHandle = family_->instanceHandle_;
-  if (instanceHandle == nullptr) {
-    return jsi::Value::null();
-  }
-
-  return instanceHandle->getInstanceHandle(runtime);
+  return family_->getInstanceHandle(runtime);
 }
 
 Tag ShadowNode::getTag() const {
@@ -341,6 +336,10 @@ const ShadowNodeFamily& ShadowNode::getFamily() const {
   return *family_;
 }
 
+ShadowNodeFamily::Shared ShadowNode::getFamilyShared() const {
+  return family_;
+}
+
 ShadowNode::Unshared ShadowNode::cloneTree(
     const ShadowNodeFamily& shadowNodeFamily,
     const std::function<ShadowNode::Unshared(const ShadowNode& oldShadowNode)>&
diff --git a/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.h b/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.h
index ae648988875ade..63c21a99617b75 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.h
+++ b/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.h
@@ -159,6 +159,8 @@ class ShadowNode : public Sealable,
 
   const ShadowNodeFamily& getFamily() const;
 
+  ShadowNodeFamily::Shared getFamilyShared() const;
+
 #pragma mark - Mutating Methods
 
   virtual void appendChild(const Shared& child);
diff --git a/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.cpp b/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.cpp
index 543ce2abe847f5..bf486802ccabc4 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.cpp
@@ -76,6 +76,14 @@ Tag ShadowNodeFamily::getTag() const {
   return tag_;
 }
 
+jsi::Value ShadowNodeFamily::getInstanceHandle(jsi::Runtime& runtime) const {
+  if (instanceHandle_ == nullptr) {
+    return jsi::Value::null();
+  }
+
+  return instanceHandle_->getInstanceHandle(runtime);
+}
+
 InstanceHandle::Shared ShadowNodeFamily::getInstanceHandle() const {
   return instanceHandle_;
 }
diff --git a/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.h b/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.h
index 203f895ff7cc16..83856089528755 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.h
+++ b/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.h
@@ -39,7 +39,7 @@ struct ShadowNodeFamilyFragment {
  * Represents all things that shadow nodes from the same family have in common.
  * To be used inside `ShadowNode` class *only*.
  */
-class ShadowNodeFamily final {
+class ShadowNodeFamily final : public jsi::NativeState {
  public:
   using Shared = std::shared_ptr<const ShadowNodeFamily>;
   using Weak = std::weak_ptr<const ShadowNodeFamily>;
@@ -122,6 +122,7 @@ class ShadowNodeFamily final {
    */
   Tag getTag() const;
 
+  jsi::Value getInstanceHandle(jsi::Runtime& runtime) const;
   InstanceHandle::Shared getInstanceHandle() const;
   void setInstanceHandle(InstanceHandle::Shared& instanceHandle) const;
 
diff --git a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.cpp b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.cpp
index 2589ee749abb1b..bc8d0c875a5e3e 100644
--- a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.cpp
@@ -16,11 +16,11 @@ namespace facebook::react {
 
 IntersectionObserver::IntersectionObserver(
     IntersectionObserverObserverId intersectionObserverId,
-    ShadowNode::Shared targetShadowNode,
+    ShadowNodeFamily::Shared targetShadowNodeFamily,
     std::vector<Float> thresholds,
     std::optional<std::vector<Float>> rootThresholds)
     : intersectionObserverId_(intersectionObserverId),
-      targetShadowNode_(std::move(targetShadowNode)),
+      targetShadowNodeFamily_(std::move(targetShadowNodeFamily)),
       thresholds_(std::move(thresholds)),
       rootThresholds_(std::move(rootThresholds)) {}
 
@@ -112,8 +112,7 @@ IntersectionObserver::updateIntersectionObservation(
       layoutableRootShadowNode != nullptr &&
       "RootShadowNode instances must always inherit from LayoutableShadowNode.");
 
-  auto targetAncestors =
-      targetShadowNode_->getFamily().getAncestors(rootShadowNode);
+  auto targetAncestors = targetShadowNodeFamily_->getAncestors(rootShadowNode);
 
   // Absolute coordinates of the root
   auto rootBoundingRect = getRootBoundingRect(*layoutableRootShadowNode);
@@ -189,7 +188,7 @@ IntersectionObserver::setIntersectingState(
     state_ = newState;
     IntersectionObserverEntry entry{
         intersectionObserverId_,
-        targetShadowNode_,
+        targetShadowNodeFamily_,
         targetBoundingRect,
         rootBoundingRect,
         intersectionRect,
@@ -212,7 +211,7 @@ IntersectionObserver::setNotIntersectingState(
     state_ = IntersectionObserverState::NotIntersecting();
     IntersectionObserverEntry entry{
         intersectionObserverId_,
-        targetShadowNode_,
+        targetShadowNodeFamily_,
         targetBoundingRect,
         rootBoundingRect,
         intersectionRect,
diff --git a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.h b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.h
index ba6a4449b366a0..89b45d83b653b7 100644
--- a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.h
+++ b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserver.h
@@ -8,7 +8,7 @@
 #pragma once
 
 #include <react/renderer/components/root/RootShadowNode.h>
-#include <react/renderer/core/ShadowNode.h>
+#include <react/renderer/core/ShadowNodeFamily.h>
 #include <react/renderer/graphics/Float.h>
 #include <react/renderer/graphics/Rect.h>
 #include <memory>
@@ -20,7 +20,7 @@ using IntersectionObserverObserverId = int32_t;
 
 struct IntersectionObserverEntry {
   IntersectionObserverObserverId intersectionObserverId;
-  ShadowNode::Shared shadowNode;
+  ShadowNodeFamily::Shared shadowNodeFamily;
   Rect targetRect;
   Rect rootRect;
   Rect intersectionRect;
@@ -28,13 +28,19 @@ struct IntersectionObserverEntry {
   // TODO(T156529385) Define `DOMHighResTimeStamp` as an alias for `double` and
   // use it here.
   double time;
+
+  bool sameShadowNodeFamily(
+      const ShadowNodeFamily& otherShadowNodeFamily) const {
+    return std::addressof(*shadowNodeFamily) ==
+        std::addressof(otherShadowNodeFamily);
+  }
 };
 
 class IntersectionObserver {
  public:
   IntersectionObserver(
       IntersectionObserverObserverId intersectionObserverId,
-      ShadowNode::Shared targetShadowNode,
+      ShadowNodeFamily::Shared targetShadowNodeFamily,
       std::vector<Float> thresholds,
       std::optional<std::vector<Float>> rootThresholds = std::nullopt);
 
@@ -51,8 +57,10 @@ class IntersectionObserver {
     return intersectionObserverId_;
   }
 
-  const ShadowNode& getTargetShadowNode() const {
-    return *targetShadowNode_;
+  bool isTargetShadowNodeFamily(
+      const ShadowNodeFamily& shadowNodeFamily) const {
+    return std::addressof(*targetShadowNodeFamily_) ==
+        std::addressof(shadowNodeFamily);
   }
 
   std::vector<Float> getThresholds() const {
@@ -75,7 +83,7 @@ class IntersectionObserver {
       double time);
 
   IntersectionObserverObserverId intersectionObserverId_;
-  ShadowNode::Shared targetShadowNode_;
+  ShadowNodeFamily::Shared targetShadowNodeFamily_;
   std::vector<Float> thresholds_;
   std::optional<std::vector<Float>> rootThresholds_;
   mutable IntersectionObserverState state_ =
diff --git a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.cpp b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.cpp
index 7fa55a5a470f18..e2ac61ae1d2de8 100644
--- a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.cpp
@@ -17,13 +17,13 @@ IntersectionObserverManager::IntersectionObserverManager() = default;
 
 void IntersectionObserverManager::observe(
     IntersectionObserverObserverId intersectionObserverId,
-    const ShadowNode::Shared& shadowNode,
+    const ShadowNodeFamily::Shared& shadowNodeFamily,
     std::vector<Float> thresholds,
     std::optional<std::vector<Float>> rootThresholds,
     const UIManager& uiManager) {
   TraceSection s("IntersectionObserverManager::observe");
 
-  auto surfaceId = shadowNode->getSurfaceId();
+  auto surfaceId = shadowNodeFamily->getSurfaceId();
 
   // The actual observer lives in the array, so we need to create it there and
   // then get a reference. Otherwise we only update its state in a copy.
@@ -36,7 +36,7 @@ void IntersectionObserverManager::observe(
     auto& observers = observersBySurfaceId_[surfaceId];
     observers.emplace_back(IntersectionObserver{
         intersectionObserverId,
-        shadowNode,
+        shadowNodeFamily,
         std::move(thresholds),
         std::move(rootThresholds)});
     observer = &observers.back();
@@ -77,13 +77,13 @@ void IntersectionObserverManager::observe(
 
 void IntersectionObserverManager::unobserve(
     IntersectionObserverObserverId intersectionObserverId,
-    const ShadowNode& shadowNode) {
+    const ShadowNodeFamily::Shared& shadowNodeFamily) {
   TraceSection s("IntersectionObserverManager::unobserve");
 
   {
     std::unique_lock lock(observersMutex_);
 
-    auto surfaceId = shadowNode.getSurfaceId();
+    auto surfaceId = shadowNodeFamily->getSurfaceId();
 
     auto observersIt = observersBySurfaceId_.find(surfaceId);
     if (observersIt == observersBySurfaceId_.end()) {
@@ -96,11 +96,10 @@ void IntersectionObserverManager::unobserve(
         std::remove_if(
             observers.begin(),
             observers.end(),
-            [intersectionObserverId, &shadowNode](const auto& observer) {
+            [intersectionObserverId, &shadowNodeFamily](const auto& observer) {
               return observer.getIntersectionObserverId() ==
                   intersectionObserverId &&
-                  ShadowNode::sameFamily(
-                         observer.getTargetShadowNode(), shadowNode);
+                  observer.isTargetShadowNodeFamily(*shadowNodeFamily);
             }),
         observers.end());
 
@@ -116,9 +115,9 @@ void IntersectionObserverManager::unobserve(
         std::remove_if(
             pendingEntries_.begin(),
             pendingEntries_.end(),
-            [intersectionObserverId, &shadowNode](const auto& entry) {
+            [intersectionObserverId, &shadowNodeFamily](const auto& entry) {
               return entry.intersectionObserverId == intersectionObserverId &&
-                  ShadowNode::sameFamily(*entry.shadowNode, shadowNode);
+                  entry.sameShadowNodeFamily(*shadowNodeFamily);
             }),
         pendingEntries_.end());
   }
diff --git a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.h b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.h
index 93ae10dd1b2ab0..af65a599203420 100644
--- a/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.h
+++ b/packages/react-native/ReactCommon/react/renderer/observers/intersection/IntersectionObserverManager.h
@@ -22,14 +22,14 @@ class IntersectionObserverManager final : public UIManagerMountHook {
 
   void observe(
       IntersectionObserverObserverId intersectionObserverId,
-      const ShadowNode::Shared& shadowNode,
+      const ShadowNodeFamily::Shared& shadowNode,
       std::vector<Float> thresholds,
       std::optional<std::vector<Float>> rootThresholds,
       const UIManager& uiManager);
 
   void unobserve(
       IntersectionObserverObserverId intersectionObserverId,
-      const ShadowNode& shadowNode);
+      const ShadowNodeFamily::Shared& shadowNode);
 
   void connect(
       UIManager& uiManager,
diff --git a/packages/react-native/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp b/packages/react-native/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp
index c5baaf76cfe440..8fed466491bea5 100644
--- a/packages/react-native/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp
@@ -235,6 +235,24 @@ jsi::Value UIManagerBinding::get(
         });
   }
 
+  if (methodName == "createShadowNodeFamilyReference") {
+    auto paramCount = 1;
+    return jsi::Function::createFromHostFunction(
+        runtime,
+        name,
+        paramCount,
+        [methodName, paramCount](
+            jsi::Runtime& runtime,
+            const jsi::Value& /*thisValue*/,
+            const jsi::Value* arguments,
+            size_t count) {
+          validateArgumentCount(runtime, methodName, paramCount, count);
+
+          auto node = shadowNodeFromValue(runtime, arguments[0]);
+          return valueFromShadowNodeFamily(runtime, node->getFamilyShared());
+        });
+  }
+
   if (methodName == "setIsJSResponder") {
     auto paramCount = 3;
     return jsi::Function::createFromHostFunction(
diff --git a/packages/react-native/ReactCommon/react/renderer/uimanager/primitives.h b/packages/react-native/ReactCommon/react/renderer/uimanager/primitives.h
index ec9ff8cf7efb2c..ee37f4ec49ec01 100644
--- a/packages/react-native/ReactCommon/react/renderer/uimanager/primitives.h
+++ b/packages/react-native/ReactCommon/react/renderer/uimanager/primitives.h
@@ -42,6 +42,16 @@ inline static ShadowNode::Shared shadowNodeFromValue(
       ->shadowNode;
 }
 
+inline static ShadowNodeFamily::Shared shadowNodeFamilyFromValue(
+    jsi::Runtime& runtime,
+    const jsi::Value& value) {
+  if (value.isNull()) {
+    return nullptr;
+  }
+
+  return value.getObject(runtime).getNativeState<ShadowNodeFamily>(runtime);
+}
+
 inline static jsi::Value valueFromShadowNode(
     jsi::Runtime& runtime,
     ShadowNode::Shared shadowNode,
@@ -60,6 +70,17 @@ inline static jsi::Value valueFromShadowNode(
   return obj;
 }
 
+inline static jsi::Value valueFromShadowNodeFamily(
+    jsi::Runtime& runtime,
+    ShadowNodeFamily::Shared shadowNodeFamily) {
+  jsi::Object obj(runtime);
+  // Need to const_cast since JSI only allows non-const pointees
+  obj.setNativeState(
+      runtime,
+      std::const_pointer_cast<ShadowNodeFamily>(std::move(shadowNodeFamily)));
+  return obj;
+}
+
 // TODO: once we no longer need to mutate the return value (appendChildToSet)
 // make this a SharedListOfShared
 inline static ShadowNode::UnsharedListOfShared shadowNodeListFromValue(
diff --git a/packages/react-native/ReactCommon/react/runtime/ReactInstance.cpp b/packages/react-native/ReactCommon/react/runtime/ReactInstance.cpp
index db92e3e75ca49e..b8a0288e4aa354 100644
--- a/packages/react-native/ReactCommon/react/runtime/ReactInstance.cpp
+++ b/packages/react-native/ReactCommon/react/runtime/ReactInstance.cpp
@@ -586,6 +586,23 @@ void ReactInstance::initializeRuntime(
                   args[1].getObject(runtime).getFunction(runtime));
               return jsi::Value::undefined();
             }));
+    
+    defineReadOnlyGlobal(
+        runtime,
+        "RN$trimMemory",
+        jsi::Function::createFromHostFunction(
+            runtime,
+            jsi::PropNameID::forAscii(
+                runtime, "RN$trimMemory"),
+            0,
+            [this](
+                jsi::Runtime& rt,
+                const jsi::Value& /*thisVal*/,
+                const jsi::Value* /*args*/,
+                size_t /*count*/) {
+                  this->handleMemoryPressureJs(15);
+              return jsi::Value::undefined();
+            }));
 
     timerManager_->attachGlobals(runtime);
 
diff --git a/packages/react-native/ReactCommon/react/runtime/platform/ios/ReactCommon/RCTInstance.mm b/packages/react-native/ReactCommon/react/runtime/platform/ios/ReactCommon/RCTInstance.mm
index e76e1d18df9946..9b99180ba51ebf 100644
--- a/packages/react-native/ReactCommon/react/runtime/platform/ios/ReactCommon/RCTInstance.mm
+++ b/packages/react-native/ReactCommon/react/runtime/platform/ios/ReactCommon/RCTInstance.mm
@@ -131,7 +131,7 @@ - (instancetype)initWithDelegate:(id<RCTInstanceDelegate>)delegate
     }
     _launchOptions = launchOptions;
 
-    if (ReactNativeFeatureFlags::enableJSRuntimeGCOnMemoryPressureOnIOS()) {
+    if (true) {
       [[NSNotificationCenter defaultCenter] addObserver:self
                                                selector:@selector(_handleMemoryWarning)
                                                    name:UIApplicationDidReceiveMemoryWarningNotification
@@ -145,7 +145,7 @@ - (instancetype)initWithDelegate:(id<RCTInstanceDelegate>)delegate
 
 - (void)dealloc
 {
-  if (ReactNativeFeatureFlags::enableJSRuntimeGCOnMemoryPressureOnIOS()) {
+  if (true) {
     [[NSNotificationCenter defaultCenter] removeObserver:self
                                                     name:UIApplicationDidReceiveMemoryWarningNotification
                                                   object:nil];
diff --git a/packages/react-native/src/private/webapis/intersectionobserver/__tests__/IntersectionObserver-itest.js b/packages/react-native/src/private/webapis/intersectionobserver/__tests__/IntersectionObserver-itest.js
index 742ea105bafb38..c6ddb1d712e2e1 100644
--- a/packages/react-native/src/private/webapis/intersectionobserver/__tests__/IntersectionObserver-itest.js
+++ b/packages/react-native/src/private/webapis/intersectionobserver/__tests__/IntersectionObserver-itest.js
@@ -15,6 +15,7 @@ import type {HostInstance} from 'react-native';
 import type IntersectionObserverType from 'react-native/src/private/webapis/intersectionobserver/IntersectionObserver';
 
 import ensureInstance from '../../../__tests__/utilities/ensureInstance';
+import {createShadowNodeReferenceCountingRef} from '../../../__tests__/utilities/ShadowNodeReferenceCounter';
 import * as Fantom from '@react-native/fantom';
 import * as React from 'react';
 import {ScrollView, View} from 'react-native';
@@ -843,6 +844,49 @@ describe('IntersectionObserver', () => {
       });
     });
 
+    // TODO (T223234714): Fix memory leak and enable this test.
+    it.skip('should not retain initial children of observed targets', () => {
+      const root = Fantom.createRoot();
+      observer = new IntersectionObserver(() => {});
+
+      const [getReferenceCount, ref] = createShadowNodeReferenceCountingRef();
+
+      const observeRef: React.RefSetter<
+        React.ElementRef<typeof View>,
+      > = instance => {
+        const element = ensureReactNativeElement(instance);
+        observer.observe(element);
+        return () => {
+          observer.unobserve(element);
+        };
+      };
+
+      function Observe({children}: $ReadOnly<{children?: React.Node}>) {
+        return <View ref={observeRef}>{children}</View>;
+      }
+
+      Fantom.runTask(() => {
+        root.render(
+          <Observe>
+            <View ref={ref} />
+          </Observe>,
+        );
+      });
+
+      expect(getReferenceCount()).toBeGreaterThan(0);
+
+      Fantom.runTask(() => {
+        root.render(<Observe />);
+      });
+
+      // TODO (T223254666): Delete this and figure out why test fails.
+      Fantom.runTask(() => {
+        root.render(<Observe />);
+      });
+
+      expect(getReferenceCount()).toBe(0);
+    });
+
     describe('rootThreshold', () => {
       it('should report partial intersecting initial state correctly', () => {
         const nodeRef = React.createRef<HostInstance>();