In comparison here is what I have found out regarding my openSUSE versions in use: 1. The stable Leap 16.1 (RC/GM) runs GNOME 48.5, which still retains the upstream X11 session code intact, included the essential gnome-session-xsession package which enables GNOME to run on X11. I replaced/configured SDDM as the login manager instead of GDM (since GDM defaults to or hides X11 options). I can now login using Gnome/Wayland or Gnome on Xorg (pure X11) and other. Leap 16.1 will be supported until October 31, 2028 2. The rolling Slowroll currently with Gnome 50.5, also retains the upstream X11 session code intact, but lacks the gnome-session-xsession package (removed since Gnome 50+). Consequently, it cannot run GNOME on X11 unless switching to another desktop environment like Xfce.