Launching the game out of the box would freeze the screen until I Alt-Tabbed out of it. After trying all the other tweaks on ProtonDB, none of which worked, I found that it tried to run on my Ryzen 7600X integrated GPU. Forcing my discrete GPU with the VKD3D_VULKAN_DEVICE=0 parameter and using Proton Experimental or Proton GE 9.5+ solved the issue (you may have to use VKD3D_VULKAN_DEVICE=1 if 0 doesn't work).