The only app I need to work on a linux phone is google maps. Although I haven't checked how good openstreet map is now. Everything else has a linux alternative
I use public transport a lot and google maps is very helpful so unfortunately can't live without it, last time I tried openstreet map it was useless for buses etc. As for alternative apps, I'm assuming I'd have trouble with, for example, banking apps, or obscure/niche apps such as my country's one for booking public transport etc.? Just nice using something that can install all Android apps OOTB