I use rsync to sync files between between my computers. This is literally the easiest and most simple way to sync files between computers, it is scriptable so you can just make a simple shell script or an alias if you don't want to type the whole command again and again. If phones had an easy enough way to rsync (and perhaps had a normal unix filesystem) I could backup more efficiently, I could sync photos between the phone and my computers more easily, I could import stuff into my phone more efficiently. But no, you have to use google sync, you have to use apple cloud or whatever and you are prohbited to do things efficiently.
Phones running GNU/Linux (or BSDs) would be an absolute dream. But the only two I can think of the pinephone and librem 5 (both of which are kinda beta-quallity). If the pinephone ever becomes usable enough and has a good camera then I may buy it, because my life will be made 90% easier.