define “most popular” please
for instance https://distrowatch.com/dwres.php?resource=popularity, does that metric fit your definition?
Anyway whatever the answer it doesn’t really matters, at the end of the day it is always Linux anyway, regardless of package manager, desktop environment or init.
I’d just warn you against Ubuntu, because its company Canonical is behaving a lot like a young Microsoft these days.
Ubuntu 100%, if you count how many distros are ubuntu based (and collaterally debian based), but I believe it is the most used one even if you only count official ubuntu releases
Maybe arch would be quite high, if you count the steamdeck as desktop (maybe), and the big increase on arch users in the past couple of years (wen’t from being rare to 1 in 3 users saying “I use arch btw”)
In professional work space, ubuntu will probably be highest. Second place I would guess Fedora
As personal workstation I would guess arch (even without steam deck) followed by mint or some flavour of Ubuntu
Chrome OS.
There is not a reliable way to determine that, by design.
