On my end, it kinda freezes the system when the game is in focus (fullscreen). But it unblocks after I Alt+Tab out (more accurately 10-15s later since it's frozen). By clicking in the menu, then Alt+Tab-ing and waiting for a while, I managed to start a new game and it seems to render well, with decent FPS.... I was looking at it with another app in-focus over the game screen, but I could only get the camera to rotate.

Specs:
OS: Manjaro KDE
GPU: Nvidia 4070 (535.113.01 drivers)
CPU: AMD Ryzen 5700X
Proton: 8.0-4 and Experimental act the same

Ok. I found this in the mesa bug tracker: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9932
And I can confirm, that after downgrading mesa to 23.1.8 the game isn't crashing anymore.
Doesn't seem to be a Proton issue then.

And I have to correct myself once more. This evening it crashed again with the same errors as above. Maybe there is more to it with this game than the mesa issue.

Not even booting on my RX580, logs below:

LogRHI: Checking if RHI D3D12 with Feature Level SM6 is supported by your system.
LogD3D12RHI: Found D3D12 adapter 0: AMD Radeon RX 580 Series (VendorId: 1002, DeviceId: 67df, SubSysId: 0000, Revision: 0000
LogD3D12RHI:   Max supported Feature Level 12_0, shader model 6.5, binding tier 3, wave ops supported, atomic64 supported
LogD3D12RHI:   Adapter has 8192MB of dedicated video memory, 0MB of dedicated system memory, and 16008MB of shared system memory, 1 output[s]
LogD3D12RHI:   Driver Version: 31.0.14051.5006 (internal:31.0.14051.5006, unified:31.0.14051.5006)
LogD3D12RHI:      Driver Date: 10-11-2023
LogD3D12RHI: Found D3D12 adapter 1: AMD Radeon RX 580 Series (RADV POLARIS10) (VendorId: 1002, DeviceId: 67df, SubSysId: 0000, Revision: 0000
LogD3D12RHI:   Max supported Feature Level 12_0, shader model 6.5, binding tier 3, wave ops supported, atomic64 supported
LogD3D12RHI:   Adapter has 8192MB of dedicated video memory, 0MB of dedicated system memory, and 16009MB of shared system memory, 1 output[s]
LogD3D12RHI:   Driver Version: Unknown (internal:Unknown, unified:Unknown)
LogD3D12RHI:      Driver Date: Unknown
LogD3D12RHI: DirectX Agility SDK runtime found.
LogD3D12RHI: Chosen D3D12 Adapter Id = 0
LogD3D12RHI: Adapter only supports up to Feature Level 'SM5', requested Feature Level was 'SM6'
LogRHI: OS: Windows 10 (21H1) [10.0.19043.UNKNOWN]
LogRHI: RHI D3D12 is not supported on your system; Windows 10 (21H1) [10.0.19043.UNKNOWN]
Message dialog closed, result: Ok, title: Message, text: DirectX 12 is not supported on your system. Try running without the -dx12 or -d3d12 command line argument.
LogWindows: FPlatformMisc::RequestExit(1)
LogWindows: FPlatformMisc::RequestExitWithStatus(1, 0)
LogCore: Engine exit requested (reason: Win RequestExit)

But a lot of other people seems to have similar issues even on windows, so it might just be the new amazing UE5 code.

Oh, goddamn, it's selecting AMDVLK instead of RADV, just realized that now. I hate myself.

Beat the demo on a ~2 weeks old build of mesa-git (3d993e63bb5) with my rx 6600, there were no hangs. The only oddity I can mention is this and it might not even be a proton issue:

I saw that happen twice after using the pods to switch locations, and both times it fixed itself after a few seconds, like the game wasn't done loading before presenting the scene.

Also frequently crashing for base game of Talos Principle 2.

System Info

OS: Freedesktop.org SDK 23.08 (Flatpak runtime)
KERNEL: 6.1.0-13-amd64CPU: Intel Core i7-9700K @ 3.60GHz
GPU: AMD Radeon RX 5700 XT (navi10, LLVM 16.0.6, DRM 3.49, 6.1.0-13-amd64)
GPU DRIVER: 4.6 Mesa 23.2.1 (git-49a47f187e)
RAM: 32 GB
Proton version: Experimental

Turned out to be a mesa issue: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10021