I can almost see how they'd get away with a review process under the guise of security, then add an app's fingerprint to some blacklist and automatically remove it from all devices.

Charging fees for sideloaded apps though? Even ignoring the part where it goes against the Digital Markets Act, how does it even work in practise? If I (as an end user) sideload some file I downloaded from the web, the developer/publisher of the file wasn't involved, possibly hasn't entered into any agreement with Apple, and won't have an account set up to pay whatever ridiculous fees Apple demand - which, of course, was the point of the DMA in the first place (freedom from a monopolistic app store).