DX12 didn't work for me neither does the Vulkan, and I tried many tinkering methods, what worked was basically switching to 6.3-8 proton and it works even with Vulkan now! i switch back to proton hotfix to play other games and back to 6.3-8 with no issues at all

runs so much smoother than on my windows 10.

although i have to mention that loading takes longer when I log in the game but it gets shorter as I play (it seems optimization problem from the developer as the graphics needs to compile)