Who would've thought? This isn’t going to fly with the EU.
Article 5.3 of the Digital Markets Act (DMA): "The gatekeeper shall not prevent business users from offering the same products or services to end users through third-party online intermediation services or through their own direct online sales channel at prices or conditions that are different from those offered through the online intermediation services of the gatekeeper."
Friendly reminder that you can sideload apps without jailbreaking or paying for a dev account using TrollStore, which utilises core trust bugs to bypass/spoof some app validation keys, on a iPhone XR or newer on iOS 14.0 up to 16.6.1. (ANY version for iPhone X and older)
Install guide: Trollstore
I suppose they can charge to use their own side-loading software, or their alternative app store, but I'm not sure what happens if a third party offers a side-loading platform that doesn't pay Apple.
I suppose they can just refuse to allow such platforms to exist, but the EU may not feels that satisfies their grievances. Eventually they're going to have to require side-loading.