Define stable! Both are non rolling distros so that means that you have the upgrade jolt every few years. I have several VMs that started off life as Ubuntu LTS around 16 so from 2016 and are still running but now on 2022.04. Those are servers so relatively simple - web, PHP, Samba, DBs, etc. PHP is a pain to fix up. Ubuntu doesn't have the rather neat slotting feature that Gentoo has so you get to do quite a lot of detective work to put it back together again. Debian is similar - again I have several systems that I manage that have gone through at least three or four Toy Story names.

Arch is rolling so there is no break and continue point. There have been some packages that have broken or been broken but not the entire system and that suits me. The QA is surprisingly good from the devs. Arch really isn't the bugbear, nightmare super ricer thingie that it is sometimes painted out to be. I find it a very thoughtfully put together distro with an awful lot of moving parts that are well integrated and a great toolset. Choice is paramount and delivered in spades without the micro management that Gentoo requires.

It also helps that I have been doing this stuff for well over two decades so some challenges are no longer the challenge they once were.