I'm not sure how we could enforce that, but maybe the law could stipulate that a certain minimum percentage of users must use 3rd party app stores, or use web apps. They should pay a fine if less than say 5% of apps are distributed outside the app store, or if less than 5% of people use a 3rd party browser engine.
If a competitor wants market share they have to build a better service. Forcing users to go with a bad deal gets the incentives all wrong and is actually bad for consumer choice.
Nice bad faith strawman, where'd you buy it ?
Apple is trying to have its cake and eat it too, selling off their devices as general computing devices and opening it partly to external developers, taking away a massive portion of profits and threatening them when it's not advantageous to them. The entire point is that you _cannot_ build a better service because Apple is blocking you.
Sony isn't getting this treatment for the PS5, despite qualifying well for being a gatekeeper, because there's no pretenses of being an open market.
If Apple wants out of this, then let them close down the App Store.