This might be related to the GPU driver check the game does at launch.
Also, why are you using vkd3d-Proton on Windows.
I've tested the game and it was 20% slower with vkd3d-Proton.
The game is crashing for me when using a lot of VRAM, i wanted to give this a try. To be precise, the nvidia driver is crashing. I have a lot of nvlddmkm error in my Windows Event Viewer, and this only happens in DX12 games what exceeding VRAM.

Doing this since december 13, i used DDU many times and used all driver version since then.
I just hoped Vulkan will fix this.
FWIW the crashes aren't related to VRAM.
It crashes on my 24GB 3090 too.
If you are using dxvk's dxgi then you might need to disable nvapiHack.
And ye, you probably won't benefit from vkd3d-proton in regards to crashing.
https://www.nvidia.com/en-us/geforce/forums/game-ready-drivers/13/516320/-/ for the crashes on native d3d12.
Thanks, crash fixed :)
VKD3D_CONFIG=dxr11x1 2023-04VKD3D_FEATURE_LEVEL=12_2x1 2023-04
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