Not sure why switching DE is important, but did you tried NixOS? It is not even immutable, it is reproducible, everything is described in a configuration file, changing it changes everything, but in a true way, like it builds everything from a config, I liked how it works, but it is time consuming to learn, search, tinker. I like keeping things simple, Silverblue does it so well for me, I guess switching to common distro is a noway for me now.