Same setup, really poor performance. Did try your steps with no improvements (had to do a extra step and blacklist i915 so xe would be used). This is really blocking me to use Qubes as my main os. Currently falling back on my mac or my arch machine for all work.
Even with these changes it goes for llvmpipe… I think the issue might be that Mesa 23… does not have the proper support for meteor lake and I think xe was added in Mesa 24… i915 seems to also fallback to llvmpipe.
Should have noticed this earlier when I wrote my HCL. My bad will check closer next time.