>because nobody made her feel like one

I'm German. Very rarely is the issue that people will in principle treat her as foreign, there's sometimes still the stereotype that you "can never be German" but in most places in the country that's not my experience.

However what is important is that you need to elbow your way in. There's a saying "nur sprechenden Menschen kann geholfen werden*. (only people who speak up can be helped). If you think someone's gonna carry you in that's not gonna happen. That's the biggest mistake I see immigrants make. It's a private and personal culture but people respect someone from the outside who shows initiative, and nobody is easily offended by someone being assertive, that's seen as a good thing.

It's not the kind of place where you can just wait and people will read what you want off your face. Doesn't even work for Germans, if you feel left out, you'll have to stand up and say you want to be in.

You hit the nail in the head.

Those who say stuff like "nobody makes me feel integrated" would also very much struggle to befriend people in their own country if they got dropped anywhere else other than their home cities away from friends and family.

Making new friends after school is hard, no matter where in the world.