Works great out of the box, works even better using d3d8to9 wrapper (https://github.com/crosire/d3d8to9/) with WINEDLLOVERRIDES="d3d8=n" PROTON_USE_D9VK=1 launch options.
proton 3.7-3x1 2018-08PROTON_USE_D9VK=1```x1 2020-02WINEDLLOVERRIDES="d3d8=n"x1 2020-02
Works flawlessly.
Specs: Proton 3.7-3, Ubuntu 18.04, NVIDIA Corporation G94GL [Quadro FX 1800] (rev a1)
Full specs: https://gist.github.com/adrianlshaw/13b21eae4d9ad3c6c79474396110feed