Comment 5 for bug 1845432

That seems likely - I suggest one of two things

  1) budgie starts spawning gsd-xsettings on demand like gnome-shell does
  2) (easier) modify bin/ubiquity-dm to only *not* launch gsd-xsettings on gnome-shell

are you up for supplying one of those changes? If (2) I'll review / upload for you. It probably looks like (in bin/ubiquity-dm in ubiquity git):

if "gnome-shell" not in wm_cmd:
    gsd += ['/usr/lib/gnome-settings-daemon/gsd-xsettings']

just after the bit where we set "gsd".