This should hopefully be fixed in the just updated Proton Experimental bleeding edge branch (see https://github.com/ValveSoftware/Proton/wiki/Proton-Versions#proton-bleeding-edge). Or well, at least the crash I see in the provided log and which I could reproduce.
The game runs for me, but I am getting a "VR headset not detected." on the desktop screen
proton experimentalx2 2025-09proton 9.0-4x1 2025-09
Compatibility Report
System Information
I confirm:
steam-1850050-experimental-10.0-20250827b.log.zip (unpacked 3.1 GB)
steam-1850050-9.0-4.log.zip
Symptoms
Game doesn't start with Proton 10 or experimental anymore. Works with 9.0-4.
Reproduction
Select Proton Experimental in compatibility, start the game. It shows a black screen on desktop, nothing in the VR HMD, after several minutes (5min+) it closes itself.
Selecting Proton 9.0-4 will install UE Pre-Requisits, then the game starts.
Using nVidia 550 driver due to issues with async reprojection in newer drivers.