Hey, after fiddling with with this since patch 8 hit, and only seeing the whole "use the dx11" version but running into constant roadblocks trying to DO that, I discovered a dirty and probably wrong way of fixing it, but its so simple. This is what I did that finally got this working as I could never get the larian launcher to work to load the correct version that works within proton and I could never get the protontricks thing to work for it.
Steps I did to get it to work:
1. Install like normal in Steam
2. Set the game to Proton-Experimental
3. us the "--skip-launcher" options
4. Use the Steam settings for the game in steam to view the files in your file manager (example mine was /home/jason/.steam/root/steamapps/common/Baldurs Gate 3/bin/) find "bg3.exe" and rename it something temporarily (I just called it "xb3.exe", then I renamed "bg3_dx11" ---> "bg3.exe".
5. launch the game in Steam as normal
This seemed to work even on my limited system resources, and if your Steam account is linked to your larian account it syncs with your cross-saves fine without needing to do any logging into larian launcher or otherwise. but I did have to set a profile in the main menu first time. So in my case by Stadia cross-saves appeared!
I hope this helps, and if anyone has better solutions than what's been put forth on
https://www.protondb.com/app/1086940 so far, please share, because us Linux peeps need luv!
