I’m on Kubuntu, so basically just Ubuntu with KDE, not sure if being on X11 or Wayland is relevant, likely not since regular Ubuntu also defaulted to Wayland now, but maybe that could be a clue on where the problem might be coming from
I tried it on KDE neon recently which is a linux distro nearly identical to Kubuntu and it worked with both a Wayland and an X11 session. The only difference between the two distros is KDE neon is strictly based on Ubuntu LTS releases and it has newer KDE software releases than Kubuntu does. I'm not sure why you are having issues. KDE neon also doesn't use snap packages by default even though Kubuntu does, but that should be unrelated to the problem as well.