Ubuntu is widely supported. If you run into any issues, you'll probably find a solution quite fast, Debian + xfce for rock solid, boring workhorse, arch if you like tinkering.
Discussion
Is Debian + XFCE with a custom, modern theme also rock solid?
I don't think the theme has a big influence, but I only use default.
I think it depends on the extent to which you rice it. You cannot tell me that all the custom ricing themes with Hyprland are stable.
This really does seem to be the most widely held consensus.