What are you trying to get out of it?

There aren't any usable UIs or apps that work well in a phone environment.

Android took until version 7 before it got good. That's with usability and usage telemetry from probably billions of devices, and Google's resources behind it.

Firefox OS went nowhere fast, and that's with Mozilla behind it.

Mobile Linux has never been a first class citizen and it's probably never going to amount to anything. The pine folks made a big deal out of getting the phone functionality to work on 2 handsets. And it's like, dude, that's pretty basic table stakes for a phone, don't you think? I get that it was technically hard, but it was kinda like celebrating your adult sibling finally mastering the spoon.

PS: anyone pointing out Android is Linux is an idiot. You know full well what OP meant by his/her question and being pedantic doesn't help.