This is not what the issue is about. The problem is that Meta is giving preference to their own ads over third party ads, not that the platforms reference one another.

The posted article is light on details. Is there another source that backs your statement?

I don't see how that link clarifies things.

  Tying its online classified ads service Facebook Marketplace to its personal social network Facebook. This means that all Facebook users automatically have access and get regularly exposed to Facebook Marketplace whether they want it or not. The Commission found that competitors of Facebook Marketplace may be foreclosed as the tie gives Facebook Marketplace a substantial distribution advantage which competitors cannot match.

This is exactly what we're talking about. EU is basically saying that Facebook.com, just by having a marketplace feature is already breaking the law.

  Unilaterally imposing unfair trading conditions on other online classified ads service providers who advertise on Meta's platforms, in particular on its very popular social networks Facebook and Instagram. This allows Meta to use ads-related data generated by other advertisers for the sole benefit of Facebook Marketplace.

Light on details.

They employ a bunch of the smartest people in the world - who all probably want to do legal stuff. I am sure they can figure out what to do to follow the law in the jurisdictions they work in.