Sorry, my mistake. DMA. However, it runs counter to the definition of antitrust law, that is the law that applies to the trust or a monopoly, an entity that controls the market. DMA instead applies to the companies of certain size, regardless whether they have market control or not.
It's a matter of interpretation. From the DMA's perspective, the iPhone is a market and thus Apple has a monopoly on that market. Likewise they consider MS to have monopoly control of the Windows market.