I wish Sailfish OS had a mention. If someone tries to escape the Android/iOS duopoly, it's probably the most mature linux based distribution out there. It's not fully open source that's true, but it can be daily driven on a number of modern(ish) compatible hardware. The most prominent of them being some of Sony's Xperia's line(official) and a slew of other older devices through the efforts of a community of enthusias…
For me, the problem with phones is the sense that you're just one step away of having no more OS updates, or updates making it slower, or basically getting locked-in in some way.
Phones feel very different to computers.