During the development cycle we (the team) were not convinced we could get SDDM to work purely under wayland mode - we were seeing things like black screens, long startup times and other issues. We think it was an issue that we were trying to use both labwc for SDDM and labwc for the desktop manager. Using weston seemed to work, but it suffered from long startup times. In Roadmap to Ubuntu Budgie 26.10 there is a goal to relook at this area.
probably this ISO 3166-1 alpha-2 - Wikipedia