from https://developer.apple.com/support/dma-and-apps-in-the-eu/#...
I have not seen this important aspect mentioned yet. Once you have opted in to Apple's new business terms, you will be locked in to those terms forever.
Because of this restriction, given the ridiculous €0.50 per year per install fees, no developer who hopes their new app will one day have more than 1M installs will choose these new terms, and I have no doubt that is exactly Apple's intention here.