HMM recognizing Frontiers but Steam gets stuck booting it up

[kuroichiraku]

Everything is fine but when I run Frontiers through HMM, Steam gets stuck and it just says "Launching". But Unleashed Recompiled works fine. I'm on Steam Deck btw

[thesupersonic16]

Uninstall the modloader from the settings, then where it says Proton, press Delete, after confirming the deletion, run the game using Steam first, then after the game has started, close it, then in HMM, where it says Proton, press the reinstall button, after it is done, press the play button on HMM.
Also make sure you start by making sure no mods and codes are enabled to ensure the mod loader is working.