There are other OSes than Linux and MacOS, in fact, one of those other OSes is far more popular than both of those put together: Windows. It has built-in openSSH support since 2018.
I'd argue windows isn't terribly popular, in that popular means "people like it more than not", but rather is used often, if grudgingly, by folks who have experienced alternatives or are unaware objectively better options exist.
I use Linux (baremetal on a System76 machine, and WSL) and Windows daily. I can’t stand OSX. As in literally want to trash it and the device it’s installed on within 10m. It’s a beautiful OS, but as a windows manager, it’s literally unusable; at least with a QWERTY keyboard. Like what genius put cmd+q right beside cmd+a, with cmd+q not even prompting the user? I could rant for days… so I’m just going to stop.
I also use Linux -- when clients require OSX on furnished equipment I cringe a bit :)
There are orders of magnitudes of UX difference between how poor Windows is versus OSX and Linux, in my mind. OSX is still worse than Linux, in part because of the inconsistency of key mappings and lack of options to make things consistent.
