Mikrotik gear absolutely runs Linux. It just uses a custom userland.
Ubiquity gear is structured the same way: It, too, absolutely runs Linux, and it uses a custom userland.
One of these userlands is friendlier than the other, but they're both still Linux.
It's a tale as old as the hills, or at least as old as the OG Linksys WRT54G
-- which was my own first foray into owning dedicated routing hardware ~20 years ago (which was -- guess what -- Linux with a custom userland). (Previous to that, I used Linux with the userland of my choosing on my desktop PC.)
Ubiquity gear is structured the same way: It, too, absolutely runs Linux, and it uses a custom userland.
One of these userlands is friendlier than the other, but they're both still Linux.
It's a tale as old as the hills, or at least as old as the OG Linksys WRT54G -- which was my own first foray into owning dedicated routing hardware ~20 years ago (which was -- guess what -- Linux with a custom userland). (Previous to that, I used Linux with the userland of my choosing on my desktop PC.)