Eh, there's no specific definition of interoperability written in the Digital Markets Act. It's decided on a case-by-case basis and I'm sure that the legislators in charge of this case will push back on this piss-poor implementation in like a year from now.

By the time this back-and-forth reaches its end, these two will find some shady b2b customers and are gonna be touted as "successful European startups".

They never got cookie popups right. What makes you so confident?