I’m not sure what “don’t fuck with immutable anything” means, but distros built with rpm-ostree (like all the Fedora immutable distros) make it easy to switch distros. You can switch from Silverblue (Gnome) to Kinoite (KDE), to Bazzite for gaming, to Aurora for development, to a growing list of other distros with a single command. And it’s not just Fedora distros either. You can try a lot without committing.
The terror will continue until you join us, then we will be nice, I promise!