Honestly, I've stated a hundred time it's preferred that people use Wine-GE for non-steam games (https://github.com/GloriousEggroll/wine-ge-custom/releases/tag/GE-Proton7-39-diablo_4_beta) but... taters gonna tate?..
Anyway this build is for people who keep using Proton builds inside Lutris instead of Wine-GE builds and/or people trying to run Diablo IV through battle.net directly on the Steam Deck without Lutris.
This release is ONLY for Diablo 4 and should -not- be needed in the future.
TLDR:
Wine commit:
GloriousEggroll/proton-wine@8c23e2e
breaks D4. Reverting it fixed it. I have no idea if this commit is needed for other games, so I advise NOT using this build for other games.