The biggest life changer to me back when I worked with Mikrotik gear was learning that the '?' character was an immediate "Show me all of the commands I can get to from the current prompt", and then appending '?' to existing commands would show all of the sub commands available etc.
From that point I found the CLI to be relatively discoverable as a way to configure the devices.
Makes sense. I guess the UI experience, including the terminal was so alien I assumed routerOS was an actual low level OS but, in retrospect, I was an idiot and of course it is Linux under the hood!
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. (Previous to that, I used Linux with the userland of my choosing on my desktop PC.)