It causes a bunch of weird controller errors, such as when a controller disconnects (or if the deck goes to sleep), it can’t reconnect again.
Just let it use the default version (which I believe should be Proton Hotfix, or whatever Valve decides it should be since BG3 is an AAA headliner, they’ll want this to work)
I’m playing it on Steam Deck right now and though I’m still only a few hours in, I’ve only had some very minor issues. The game plays fine!
Issue 1: The graphics settings don’t seem be persisted. I have to manually activate anti-aliasing every time, or deal with jaggies.
Issue 2: On Proton Experimental, my controller didn’t work at the start. I was able to fix it by launching the on-screen KB (Steam button+X), hitting “Enter”, and then switching back to controller mode. Sounds like it’s time to switch to Proton Hotfix.
Otherwise, it’s been great! I left the graphics settings (other than AA) at their defaults and I’ve seen no noticeable lag or stuttering during play.