I think we can expect Starlink to have similar coverage to GPS: great in the country, useless in my bedroom in a multi-story building. Also the expected receiver size for Starlink is an order of magnitude bigger than the one for a cellular network.
For phones, tracking, etc the cellular network would still be superior. Something like a car might go with both starlink and cellular because anywhere where one is weak the other is likely to be strong.
Or put in on the side of the building like regular satellite dishes. But realistically any apartment building that's not in the middle of nowhere will be better served by fiber anyways. Once you have multiple customers in the same building they will quickly feel the limit of how much bandwidth you can push to a small area throught the air from 500km away.
For phones, tracking, etc the cellular network would still be superior. Something like a car might go with both starlink and cellular because anywhere where one is weak the other is likely to be strong.