I had an NTC CHIP (single core ARM with 0.5 GB RAM 4GB NAND storage) running Debian Jessie with a LiPo battery few years back that had nearly 2 years uptime… Rock solid reliable…
But I prefer more “cutting” edge stuff, hence why I run Ubuntu, and will be slowly migrating to 21.10 next month, then 22.04 LTS in April next year…
If you want rock solid reliability and maybe 3 year lifecycle, without all the shiny bling : Debian…
If you want a longer “LTS” lifecycle, e.g. 5-8 yeas, and some of the shiny bells n whistles (and a shitload of shits n giggles maybe) - then maybe Ubuntu server? I prefer it to any offerings from Red Hat or “EL family” (RPM distros like Fedora, Oracle, CentOS [dead soon anyway]).
One of my customers is still running some Debian 3.0!!! Yeah!!! I hate it… it’s just laziness on their part not porting their “bespoke” piece of shit app to a later release (or even spending any time to figure out if it will run on something else!)… but it’s reasonably reliable, still, I guess… no security updates of course!
I always say “horses for courses”…