Does Apple require "in app purchases" to be added?

Question

Apple Developer Program

There is an application for selling e-books and audiobooks
. Payment methods are made using domestic banks, and PayPal is available for foreign customers.

Apple requires the addition of an "in app purchase" in the app.
and does not accept!

Apple has a slightly higher tax of 30%
We don't want to connect this service to our application

Are there any other methods?

Answer 1

They have every right to do so.

Answer 2

Since you don't have a physical product or service, you must use In-App Purchase.
This is, let's say, the Apple tax :).
Can be read in the App Store Review Guidelines :

3.1.5 (a) Physical Goods and Services Outside of the App: If your app enables people to purchase goods or services that will be consumed outside of the app, you must use purchase methods other than in-app purchases to collect those payments, such as Apple Pay or traditional credit card entry.