As you mentioned, you need the latest Mesa(ATM git master). With that I had no issues.
For ray tracing, the only thing which enables it for me is using the VKD3D_CONFIG=dxr11 environment variable, but it would get so slow in forest and around water that made me disable it.
Just wanted to say that it seems DXR is enabled by default in vkd3d version 2.11 https://github.com/HansKristian-Work/vkd3d-proton/releases/tag/v2.11