You're not allowed to sell digital goods, including things like feature unlocks or paid upgrades, via your own payment mechanism (which Apple Pay requires). You

You're not allowed to sell digital goods, including things like feature unlocks or paid upgrades, via your own payment mechanism (which Apple Pay requires). You have to use in app purchase so Apple can take their cut, and so the transaction is between the user and Apple, not the user and you. So no, this isn't a feasible solution, unfortunately.