Who I have the same questioned this topic

Have an unlocked Note 20 ultra.  5g was not working, could not subscribe to call filter plus or visual voicemail, and no carrier billing on playstore. Flashed full verizon firmware (N986U) and got 5g to work. However call filter visual voicemail and carrier billing is still not working. Read that these features wont work on unlocked phone....but should work with carrier firmware correct? Or does it have to do with a unlocked sim.