I get the spirit of the DMA. I get the whole designation of gatekeepers and do agree Apple is a closed ecosystem. What I don't understand are the implementation

I get the spirit of the DMA. I get the whole designation of gatekeepers and do agree Apple is a closed ecosystem. What I don't understand are the implementation details and I always hear "it is complex". Let's stick with earbuds or watches, where the argument (e.g. Garmin) is that they can't create functionally equal devices to AirPod / Apple Watch, because not all APIs are open. I understand this point, since yes, Apple has a lot of internal implementation that only Apple can use for their devices. What I don't understand is the EU's standpoint of "just opening it up(!)". Let's say Apple would allow everyone to use all APIs to communicate with their AirPods/Apple Watches. Assume everything is open now - wouldn't that create chaos? Another vendor could implement everything Apple does and release similar AirPods or Watch with whatever hardware quality - but what happens when Apple changes their internal implementation? Changes the implementation every week, because they optimize for THEIR devices. There is no official ISO standard, Bluetooth standard or whatever standard they are adhering to, they would just open up their implementation. I assume the EU would then say "this is against the spirit of the DMA, do not change your implementation so often", but this would seem like a very long cat and mouse game (it already is a very long process). Why doesn't the EU define some interoperability requirements that gatekeepers need to adhere to in the EU market? This would make it easier for everyone. I don't get why it always is just the talk about "open it up" - that would be a start in terms of interoperability, no doubt, but that isn't the solution is it?