CPU: i5-7400
GPU: Sapphire Nitro+ Vega 56
Distro: Solus Budgie 64bit, everything up to date.
Proton: 5.6 GE-2
Kernel: 5.5.11-151
Mesa: 19.3.4-139(ACO enabled)
Game runs smoothly no stuttering or fps problems. However small rectangular artifacts appear almost everywhere making the experience very much less enjoyable.
Image example: noticable on the flag under the Doom Slayer)