What's not cool, and what I was excited for DMA to fix, is that Apple says that by transacting with a customer _by any means_ on their platform, you owe them a part of that transaction. This is anathema to a free market. Again, it's fine if they charge you for using their payment platform, or even alternate payments made through some Apple payment UI. What's not fine is forcing anyone who wants to sell you a good or service to have to compete with the smartphone market as a whole to access you as a customer unimpeded. It is especially egregious that Apple prevented you from as much as mentioning that alternative payment methods exist off-platform.
So the biggest issue in my eyes isn't that Apple is charging per install, it's that they're charging to so much as mention that you are able to transact elsewhere, both in the per install cost and in still taking a commission. That is tying and that should be illegal. It is like if a leading browser blocked websites from companies that refused to share their profits, regardless of if that transaction even happened through the browser.