NixOS will get you there (or anywhere, to any version, of any thing, and/or back again) just by pinning any conceivable package (and it has more than any other Linux distro) to a particular nixpkgs hash.

I thought of this because it sounds like one of the reasons you're not upgrading it is fearing the risk of it fucking everything up and it being a pain to roll back (your "it ain't broke, so why fix it?" is a hallmark of that mentality). Well...

I will never use another Linux distro for this specific reason. NixOS is the complete freedom to dip in, dip out, roll back on problems, try new things out, etc. The freedom to experiment, try it, back out if there's any issue... but with seatbelts, thanks to the declarative nature of everything (as well as being able to pick previous "instances" on boot).

Afraid of Nix (the language)? LLM's make that trivial these days. For example, I just did something like this today: "Instead of using the one in nixpkgs, whose build has issues on my hardware, set up a derivation that uses its git repo and compiles that instead." A minute later, boom. Declarative working glory, forever.