Have you tried Fedora Silverblue[1] and its cousins? `root` is an immutable image powered by something akin to `git` but for OS files. You can layer RPMs (although you should use flatpak or containers wherever possible) and /etc is mutable but also tied to the deployed image[2]. You can rollback your system to previous images, rebase it to a completely different system (i.e from `silverblue/gnome` to `kinoite/plasma`) or build your own OS image for deployment instead.
It is a different desktop paradigm for sure (for one, you won't be using a standard package manager) and you do feel its rough edges sometimes, but it is my favorite Linux experience so far, where the OS doesn't stay on my way unless I want it to be in the way: I turn my PC on, use it as usual, desktop apps are updated on background with GNOME Software/flatpak and if there is a new image available, as soon as I reboot/shutdown, next time it is up, everything has been cleanly applied. Flatpak'd apps also won't spread files across the system, so everything is as self-contained as it can be.
[1] https://fedoraproject.org/silverblue/ [2] https://ostree.readthedocs.io/en/stable/manual/introduction/