I guess the games part applies to you, and may apply to me as well.
One thing to always remember: if it only runs on Linux because of Proton, it can stop working at any time based on any related update.
You’re gonna have to go through the whole shebang to get it working again, or wait for a new Proton update or driver update, and play other games for now.
The Shebang:
- Try different sessions — Wayland or X11
- Try different Proton versions
- Try different launch options (using gamescope or something else)
- Try different kernels (can help, but may not in this particular case)
- Downgrade packages (not recommended)