> But are they maintained well?

Alma has a few affordances as it's no longer RHEL source compatible, which means it could ship priviledge escalation fixes with new kernel updates faster.

Rocky responded with an extra, optional to enable, security repo to provide mitigations to the exploits while waiting for RHEL to downstream.

Look pretty well maintained to me. If only judging by recent events.

For a while (a decade+), I was running CentOS on my servers on the same assumption of long time stability and ensuing peace of mind. Then I figured that over such durations, the ecosystem drift becomes significant and keeping applications up to date and running on top of the OS becomes an increasing challenge (with the more "infrastructure" packages like glibc, python/Apache combos, GCC, ... slowly becoming incompatible with the latest applicative stack).

Then I figured that version upgrades were miserable, not just because I had painted myself in a weird corner with ungodly packages mix-ups, but because the upgrade path was always best-effort. I think I gave up during the 6 to 7 transition, as I realised that all I needed was fedora: with yearly or half-yearly updates I have no need to fight the distro's packages: stuff stays current and in working order, major distro upgrades go smoothly, downtime is minimal. I'm not considering going back to any "server distribution" ever.

You are betting that whatever you host doesn't live as long as the upgrade cycle because it'll probably be a pain when the upgrades finally arrive. I'd rather have smaller version jumps more often than a huge jump with everything changing after a long time.

Alma and Rocky if you want fully free or have a lot of machines. RHEL if you are okay with registering with them; they give ten machines free access to their updates for each Registered account in their system.

RHEL is definitely the most stable major distribution. Alma and Rocky are essentially downstream clones of RHEL.

I would say NixOS, where it is trivial to switch across releases, run software from different releases, and perform rollbacks.

I have been running NixOS on several servers for more than a decade. No reinstalling, upgrading, or any breaks whatsoever.

Debian LTS/extended LTS

Probably Debian or Ubuntu. The question is...why do you care that much?

I've upgraded Debian stable (both pure and with some cherry-picked backports) and Ubuntu (non-LTS and LTS) systems in place and rarely broken anything, for years and years. When stuff has broken it's been a quick google and then slapping myself for not having read the upgrade guide.

I do generally wait about 2-3 weeks before upgrading, giving time for them to catch stuff that was missed until the great masses were set loose on it.

[dead]

Use a rolling release like Arch and it’s supported forever.