I tried a number of things to get this working, including different versions of Proton, trying to force it to use DirectX 9 or 10, and trying to get it to load without using DXVK entirely. Nothing ever worked. It would either fail silently or I would get an error message that said:

assertion failed 'HaltMsg' Failed to Create DX11 Device hr=887a0001 Dx11GraphicsInterface::GraphicsInterfaceAttach (d:\ax_google\trunk\ax2017\engine\windows\windowsdx11.cpp:1583)