

Enabling xbox controller support resolved the issue
Works perfectly with Proton Experimental. Default Proton can't play the opening cinematic, otherwise is perfect.
I only played through the first act, but the game ran perfect. Only the opening videos didn't work, but that was resolved using Proton Experimental. Would be worth trying GE as well. This game should be "playable" by the listing, not unsupported (which is very misleading).

6.5-GE-2 GloriousEggroll
Steam input didn't work for my ps5 controller, dropping back to 6.5-GE-2 and disabling steam input for some reason lets it work, changing to a newer version or turning steam input on gives me no controller support.
Aside from controller support Proton Experimental and Proton 6.3.7 also worked, 6.5-GE-2 was the only one I could get the controller to work in though.

Only Proton 6.5-GE-2 had my controller, cinematics, and V-Sync all working. Other versions of GE had one of those things broken. Also, changing Proton versions would delete my saves, so be aware.