I find it funny calling Arch “less stable”, because I’m inclined to find it
more stable, for my purposes, skills and attitudes.
I’ve administered at least one each of: Ubuntu server (set up by another; the rest were by me), Ubuntu desktop at least ten years ago, Arch desktop, Arch server.
The Arch machines get very occasional breakages, generally either very obvious, or signposted well. I did have real trouble once, but that was connected with cutting corners while updating a laptop that had been switched off for two years. (I’ve updated by more than a year at least two other times, with no problems beyond having to update the keyring package manually before doing the rest. The specific corners I cut this one time led to the post-upgrade hooks not running, and I simply forgot to trigger them manually in order to redo the initcpio image, because I was in a hurry. Due to boot process changes, maybe it was zstd stuff, can’t remember, it wouldn’t boot until I fixed it via booting from a USB drive and chrooting into it and running the hooks.)
Now Ubuntu… within a distro release it’s no trouble, except that you’re more likely to need to add external package sources, which will cause trouble later. I feel like Ubuntu release upgrades have caused a lot more pain than Arch ever did. Partly that may be due to differences in the sorts of packages that are installed on the machines, and partly it may be due to having used third-party repositories and/or PPAs, but there were reasons why those things had to be added, whether because software or OS were too old or too new, and none of them would have been needed under Arch (maybe a few AUR packages, but ones where there would have been no trouble). You could say that I saw more trouble from Ubuntu because I was using it wrong, but… it wouldn’t have been suitable without so “using it wrong”.