Compiling with your new 4 patches and enabling “--with-vulkan”, "libplacebo" and "libzimg" gives me no errors. But the results are the same: The GPU only works with X11-OpenGL and behaves the same with “none”, “vaapi”, “vdpau” and "vulkan".

So I think it's still my system's fault (or mine) and the only thing I can say is that your patches don't cause any problems.