Calling is something that works in e.g. Postmarket OS. The trickier parts are NFC payments, lack of apps. So it comes with huge drawbacks. Some apps can even require that your device is verified by google and you have no way of hijacking it.

Proprietary camera software is also a huge thing. Software can do so much thing and you pay for the software also, not just the hardware but you lose the software when you install something other than the factory default.

And battery optimization is very young in desktop grade linux OSes, you won’t get that good battery life as with android.