i did a retest with proton-5.0-10b and proton-5.13-2, the artefacts are gone now.
Intro Issue remains, but the same happens on my Windows 7 Machine too. I tried protontricks 34820 wmp9 wmp10 wmp11, without success.
proton 5.0-10bx1 2020-12proton 5.13-2x1 2020-12PROTON_USE_WINED3D=0x1 2020-05PROTON_USE_WINED3D=0:x1 2020-05PROTON_USE_WINED3D=1:x1 2020-05
Compatibility Report
System Information
I confirm:
Symptoms
Reproduction
Logs
PROTON_USE_WINED3D=1: steam-34820_PROTON_USE_WINED3D=1.log
PROTON_USE_WINED3D=0: steam-34820_PROTON_USE_WINED3D=0.log
Videos:
How the Glitches, Artefacts look like