The ACM ruling is quite clear about that: they point out that modern dating utilities require the infrastructure offered by Apple's and Google's platform, such as reliable delivery of notifications, geolocation, etc. These are all possible to some extend on the web, however it's clear that native applications can hook into background refresh, etc.
The law?

The EU is putting forward legislation to consider app stores and other platforms as utilities (well, except that they call them
gatekeepers):
Discover how the Digital Markets Act ensures large online platforms in the EU behave fairly, and allows new players to enter the market, thus developing a fast evolving digital sector.
ec.europa.eu
So, stronger regulation is coming. It's FAANG's own fault, if they cannot regulate themselves and abuse users/businesses, it's time to regulate them. But I realize that this is my perspective through mainland European glasses. In contrast to what others in this thread say (
it's a money grab,
corrupt governments), this is what we do in Europe. European businesses are regulated as well and often it's good for consumers (e.g., we have far better warranty than in other places).