To start: There absolutely should be limits to what kinds of devices can be sold. E.g., they should not be dangerous to operate. If you can't make a lawnmower that doesn't harm people, it's OK for governments or the EU to tell you that you can't sell lawnmowers. It's also OK to enforce standardization in e.g. electrical sockets and other basic infrastructure. This should not come down to "consumer preference" - _especially_ not when the harms aren't obvious at the time of purchase.

Apple's total control of all aspects of the iPhone platform is harmful to consumers in a way that is not at all obvious, especially not to the less technologically literate.

An obviously absurd analogy is if a hammer company was somehow able to force you to use their brand of nails and wood and charge you per annum for the use of whatever you built. We did not have previous legislation to handle this situation, because simple physics means that can't happen. But with modern-day complicated tools, it can, and so some regulation of this sector is absolutely needed.

(I don't know the DMA well enough to say if it, specifically, is the right way to handle it, mind, but it's obvious to me that the present situation is untenable.)