In the scenarios where a user is paying for something that is delivered or executed by the app developer’s infrastructure, digital or not, Apple is a payment gateway, not a publisher. They can either match Stripe or go to Paddle’s rate of 5% because they handle taxes and VAT etc. But either way they are and should act as payment gateway and merchant of record, not publisher.
This distinction already exists for on digital goods. No one expects to pay 30% when selling food or groceries, for example. But digital services are the same thing.