Does it run as badly with DXVK on Windows as well? Based on videos like this one, the game should be running fine.
So @K0bin has had a look at the game and it seems like this game tries to read data that's supposed to be write-only and is therefore in uncached memory, i.e. a game bug.
proton 5.0x1 2020-08
So this game has well known issues related to Media Foundation.
Aside that, the game has really bad performance on official Proton 5.0.9 with AMD Ryzen 5 2600 and Nvidia GTX 1060, which is strange since it should be a d3d11game. Frame rate constantly drops from 60 fps to 20 fps, with both cpu and gpu loads sitting around 30 - 40%
Obviously it works flawlessly on Windows.
If you show me a tutorial on how to make a d3d11 api trace i'll be glad to post the log.