I am currently looking at using OpenSUSE Micro OS for a home server. It is based on Tumbleweed and also rolling release, but it has an immutable filesystem and can automatically update and rollback. It’s similar to Fedora Core OS, which was my first choice, until the Red Hat drama.
Unstable is and from what I’ve heard, nixpkgs even is one of the fastest repos with updating packages (also the largest). But I still wouldn’t recommend it for OP.