Same, from YouTube it looks like this is the end of the game, but you're supposed to get a credits sequence, not crash
Edit: It's fixed in 0.4.0.3
I also had this happen when I entered the fog. Nothing fixed it besides restarting the game
Edit: it should be fixed according to 0.4.0.3 patch notes
I added PaperRPG.exe to steam and set the compatibility layer to UMU-Proton-9.0-3.2. I'm also on the steam deck beta if that makes a difference
Yes it worked fine on a steam deck