That policy has really killed a lot of functionality on macOS. I suspect it will cause fiction on iOS when the EU forces them to allow alternative install sources.
Personally, it grates me when Apple cripples functionality this way to try to keep us stuck in their platform. Can't use Firefox with Keychain. You can only view your current Apple Card balance on an iOS device -- not even a macOS device. At the end of the day, I hate being manipulated so much that it actually pushes me away from the platform to see this scummy behavior.