Applications start on the wrong display

[jffz]

I am currently trying to replicate the setup I had with the legacy sunshine but am currently stuck on an early stage of it.
I achieve to run steam applications through moondeckbuddy but they start on the wrong display. I can hear the sound on the moonlight client but display is sent to my main computer monitor.
On a related topic, I was making use of a dummy hdmi plug with my legacy setup to be able to run games without making use of the principal screen. Would I still need it with Apollo?

sorry if this lack a bit of context, I'm not sure exactly where to start. Thanks for your time.

[ClassicOldSong]

You don't need a dummy plug. What you need is start a virtual display session, and in Windows settings make the virtual display primary or the only active display. Then you can terminate the session and start other applications, Windows will automatically apply your previous setup.

You only need to do this once per client.

[jffz]

Definitely the solution, thanks a lot for your reactivity.
Might abuse your time in this discussion but still a few points to clarify on my side.
When closing a session, game doesn't exit.

[2025-11-23 17:55:21.699]: Error: [D:\AutoHotkey\pause.ahk] failed with code [259]
[2025-11-23 17:55:25.088]: Info: App did not respond to a graceful termination request. Forcefully terminating the app's processes.
[2025-11-23 17:55:25.088]: Info: Executing Undo Cmd: [D:\AutoHotkey\resume.ahk]
[2025-11-23 17:55:25.090]: Info: Resolved user-provided command 'D:\AutoHotkey\resume.ahk' to '"C:\Program Files\AutoHotkey\UX\AutoHotkeyUX.exe" "C:\Program Files\AutoHotkey\UX\launcher.ahk" "D:\AutoHotkey\resume.ahk" '
[2025-11-23 17:55:25.092]: Info: D:\AutoHotkey\resume.ahk running with PID 3024
[2025-11-23 17:55:25.119]: Warning: Return code [259]

[ClassicOldSong]

Expected behavior, you should quit the game instead

MoonDeck buddy tracks the game but not the session.