photo resolution no correct on sony Z5P

[#1]

my model is E6883 ,android 5.1.1, run the. Latest lightroom mobile ver . This device has a 23M back camera but Lr only takes at 4K that only match screen resolution , can this problem been fixed? For which I know there might not have many people use it.

[#2]

Is this a limit imposed by Sony?  I gather other camera apps, though not all, are also restricted in resolution.