> As Epic has said they think they should have to pay nothing for all that Apple provides.
As they should be. iOS was already paid for when the user bought their device. Mandating a 30% cut on all in-app purchases is double-billing.
Tim Kulak[0] calls this "forcing Apple to give away its technology for free", which is asshole logic. In no sane world would a court consider application developers to be making a derivative work of the OS they port to, so the OS vendor has no legal entitlement to application developers' revenue. The only world in which this stupid 30% cut was even tolerated was, ironically for Epic, games development.
As for privacy and security concerns, I would like to note that Apple has very specific definitions of those words that only marginally interact with your own understanding. To be clear, if you were to modify an iOS app to, say, remove tracking code from it, Apple would consider that a security breach. Even though this is a common thing that we do in web browsers all the time. Because users have their hands tied on iOS in ways that they don't on macOS, they can't fight back against tracking on their phones like they can on their computers.
[0] Term used by the Soviet government to refer to "any rural landowner that didn't cooperate with their disastrous attempts at land collectivization". I'm using it here mainly because it almost-rhymes.