I read in one of the posts here that even with the Universal Blue capability of allow the user to switch Fedora OS versions, still causes a little bit of mayhem when switching Desktop Environments, such as switching from Plasma to Gnome, or viceversa. Or hyprland , or i3 WM.
As I continue to explore Nix, I found that there is a feature called Home Manager that could offer a clean solution when one switches DEs. The examples I’ve seen are more about auto-update of the dot-files in the user directory, but it can be easily be adapted to the Gnome/Plasma configuration folders. You just write a nix file for each of your different DEs and apply it when you reboot with a different Fedora Silverblue or Universal Blue derivative.
This is one of the best videos on the subject of Nix Home Manager.