Well... no, it's not. As long as device owners can choose which and how many app stores are on their device, regulators and courts will be satisfied. If users then choose number_of_app-stores == 1 and app_store_provider == "Apple", that's the user's choice - and for many users, like Grandma, that may be the right choice.

Regulators have never ruled that Apple can't have an app store or that the number of enabled App Stores MUST be more than 1 - only that the legal owner of the device have an opportunity to choose. Scenarios like "Oh no, the EU wants to take away Grandma's one safe, simple walled-garden app store so she's left to fend for herself on the dark web" is a disingenuous straw man exaggeration by Apple and their apologists to protect Apple's multi-billion dollar app store monopoly.

Once there's owner choice, even Grandma who chooses Apple as her only app store will pay lower prices and very likely gain other safe options like a full featured Firefox with Ublock Origin ad blocking. Just the existence of competitive choice is beneficial - even to users who choose "no competition". Plus Apple will finally have a real incentive to be more responsive and reasonable with app developers regarding app store prices and policies - which will help solo and small startup app developers.