With most DEs, the background tasks that implement the various guest additions are started by the /etc/X11/xinit.d/98vboxadd-xclient script. Under GNOME in Mageia 7, that script was only run if GNOME was forced to use X11. Under GNOME in Mageia 8, that script is never run, regardless of whether GNOME is using X11 or Wayland. This means the guest features (such as the bi-directional clipboard or automatic display resizing when using the VMSVGA controller) don't work out of the box.

I think this could be fixed either by using an XDG autostart file or by using a systemd user service.

From reading around on this subject, I think we also need to add the VBoxDRMClient utility to virtualbox-guest-additions to get display resizing working under Wayland.