I’d done that a few days ago, but you’re right, not specifically to these suggestions. I tried the export VKD3D_DISABLE_EXTENSIONS=VK_EXT_mesh_shader VKD3D_FEATURE_LEVEL=12_0 VKD3D_SHADER_MODEL=6_5 %command% and variations of it. It reduced performance significantly, so would not suggest people on more recent Mesa versions try this anymore. When I looked into it, it seemed to mainly be in place for Mesa 22.x which was still lacking mesh shader support.
It’s not a patient game yet, but I caved and got Alan Wake 2 the other week. In the early stages so far (the game’s quite scary!) but loving it.