I have no knowledge about or experience with immutable distros, but I’ve been maining the Fedora KDE spin on my laptop for several major releases now and so far have found no reason to switch away from it. The Plasma Wayland session has been solid from the beginning and everything has just worked.
A full Hyprland DE with top bar, quick settings and app launcher, with unified looks and centralized setings would actually be awesome and might make me switch
Not trying to immediately change your mind, but Garuda added a Hyprland spin with their latest release. Boot into the live ISO and see what you think.
It also uses the Red Hat RPM package format and a different package manager. But it just amounts to a few different commands to learn if you manage packages on the command line.