I don't know if fragmented is the right word. Just like desktop Linux, mobile Linux has pretty much settled on one major standard (Phosh a la Gnome) and slightly less popular alternative (Plasma Mobile a la KDE). Sure, you can go about customizing it to your whims, but fragmentation isn't nearly that bad, especially since the distribution options are so much lesser.
The problem really is getting the commercial software people want on the phone. But if you just want to use it as a phone (e.g. no special apps or mobile games), it does most of that in a pretty streamlined manner (albeit, rougher than the commercial options).
The problem really is getting the commercial software people want on the phone. But if you just want to use it as a phone (e.g. no special apps or mobile games), it does most of that in a pretty streamlined manner (albeit, rougher than the commercial options).