I tried running the game without setting a Proton version but it complaints about graphics (A D3D11-compatible GPU (Feature Level 11.0, Shader Model 5.0) is required to run the engine). After setting compatibility Proton to 9.0-4 it works perfectly. It does takes some time to boot when you hit Play, but once is up, eveything runs as expected. When logging in there some black windows but after some seconds it goes away. I've set the DX11 option in the launcher per recommend here in ProtonDB by user tjandra. I did not used MangoHUD, so no launch options were set.