You don't have a duty to hire in USA, but you can still get in trouble for illegally firing someone for the wrong cause. Same applies here, this isn't rocket science.
> 6. The gatekeeper shall not directly or indirectly prevent or restrict business users or end users from raising any issue of non-compliance with the relevant Union or national law by the gatekeeper with any relevant public authority, including national courts, related to any practice of the gatekeeper. This is without prejudice to the right of business users and gatekeepers to lay down in their agreements the terms of use of lawful complaints-handling mechanisms.
I am not 100% certain that would apply here, but if the DMA doesn't protect against these things then I am pretty sure that EU will plug that hole to ensure gatekeepers can't retaliate unfairly.
They've been throwing tantrums against every company they deal with. They want to charge fees on their store and platforms. They want their IAP. But they act offended when any other company wants to charge them to be on their stores.
This is because Epic did things like pushing a hidden IAP system inside Fortnite to evade review and then at a later point switching it on. This sort of thing has been forbidden since the early days of the App Store. It is a fundamental part of the Apple-Developer contract that you allow reviewers access to all functionality.
[1] https://law.justia.com/cases/federal/appellate-courts/ca9/21...
I can understand that Apple wants to safeguard their platform by requiring notarization, etc. But they are playing with fire here. One outcome of misbehaving could be that the EC will require full sideloading (Android-style), so that Apple cannot sabotage third party stores anymore, like they are doing now.