Arch + EndeavourOS aur

I had to manually install sudo pacman -S vulkan-radeon

Before it would either install or launch. Without it, the installer crashed, and eos64 was just stuck on a black screen. Also make sure that PROTON_USE_WINED3D=1 %command% is removed from Launch Options under Settings - not sure if that was necessary for the installer to run.

Can run from CLI with: STEAM_COMPAT_CLIENT_INSTALL_PATH="$HOME/.local/share/Steam" STEAM_COMPAT_DATA_PATH="$HOME/.local/share/Steam/steamapps/compatdata/306130" WINEDEBUG=+seh python3 $HOME/.local/share/Steam/Steamapps/common/Proton\ -\ Experimental/proton run zosSteamStarter.exe

The WINEDEBUG part was useful to figure out what was missing.

Steam should really check and recommend vulkan dependencies. Or each Distribution should package them as prerequisites. As mentioned, sudo pacman -S vulkan-radeon fixed it for me. I think the Ubuntu equivalent is sudo apt-get install mesa-vulkan-drivers