From my understanding (I also don't have an iPhone), you're not sent anywhere, because Netflix were forbidden from telling you to go sign up on their website. There was just no sign up button, and an implicit assumption that you would somehow figure out that you need to open up netflix.com in the browser and subscribe there.

I think that has changed now for Netflix in particular, but not for some other types of apps?

No, that's called steering and it would be perfectly fine. But apple doesn't allow that, and that's what the EU's major complaint is about. So the worst case is that you have no competition, which is the definition of anticompetitive