I would say Linux Mint, very stable, good attention to detail from the devs. I like MATE, have been running this for years now. It's upgradable, lots of packages, no snaps by default.
That still would have to be Arch. From what I have heard elsewhere, I would suggest Debian for its extreme stability. You won't get the newest stuff, but Debian is really focused on making sure nothing breaks between updates.
Is that Debian? I want it desktop-focused actually and that works great with multi-monitor and proprietary drivers from NVidia.
Currently on Ubuntu but I see bugs here and there and a software update messed up my desktop a few weeks ago. It is for work. I do NOT want to waste time with unstable stuff.