Buying a physical good or an upgrade to a physical good isn’t an “in-app” purchase. I don’t think Apple is taking a cut here — it’s probably just Apple Pay.
> Apple currently takes a 30% commission from the total price of paid apps and in-app purchases from the App Store. For some small app makers, the new policy could cut the amount that they pay Apple in half.
https://www.cnbc.com/2020/11/18/apple-will-cut-app-store-fee...