Personally I am excited for immutable distributions, so my suggestion would be Fedora Silverblue or Kinoite. It may be a spin of Fedora, but it works completely differently than regular Fedora. I am using it as my daily driver for over a year already and I am quite happy with it (apart from reoccurring breakages caused by kernel updates, e. g. my AMD desktop currently does not work with kernel 6.4 or newer, but this doesn't have anything to do with Silverblue).
There are other immutable distributions out there, e. g. Vanilla OS or openSUSE microOS, so if you really want to avoid Fedora, you could also choose trying out one of these. In the case of Vanilla OS I would wait until version 2 is out, because version 2 will be radically different from the first release.
My recommendation is F-Droid Basic. It's a more modern official client that supports automatic unattended updates on Android 12 and newer.