They are following the SC ruling which has explicitly given them the right to do so.
- anti competitive to force users to use their *Payment Processing* platform.
- not anti-competitive to charge 30% for purchases made from the app
The justification is that you're getting access to Apple's network of customers as "leads" and by referring them to you for purchases, Apple is justified a 27% commission.
Similar, other major digital market players such as MS, Google, Nintendo, Sony, Valve all charges 30% as a platform commission fee.
The end result is what you see now. Payment flows originating from the App, Apple is entitled to 27% (-3% which was judged to be an appropriate transaction fee for the Payment Processing).
Apple will not charge you 30% for any purchases made organically through Safari. This was not in the ruling and this remains functionally as it is now.
You can debate about the 30% being too high, especially on top of an annual fee. But claiming that all Safari purchases will incur 30% is a strawman.