I've never made an iOS app and don't have plans to. But my assumption is ~every >= medium-sized iOS app would be monetised by selling data to aggregators.
Even if that was the case - which it isn't - the aggregator data isn't keyed by the user in question. That is highly illegal pretty much everywhere and would get you in a lot of trouble. You can't "just" find out which apps an arbitrary person has installed on their phone. That's not how it works.
Even if that was the case - which it isn't - the aggregator data isn't keyed by the user in question. That is highly illegal pretty much everywhere and would get you in a lot of trouble. You can't "just" find out which apps an arbitrary person has installed on their phone. That's not how it works.