It's fine if she's truly happy.
She doesn't, in all honesty, sound as though she is.
The friends adding her to groups isn't bullying- I initially read that as they add her and kick her out, not that they add her and then she leaves the group.
It sounds like she hasn't yet found a friend or group of friends she's comfortable with, but the "I don't care" (she does) and the comments about not wanting to hang out with "unpopular" girls shows that she's not happy with her situation.
The anxiety also obviously probably stops her from feeling comfortable in certain social situations.
Many posters on here have described their own children and they sound perfectly happy. The OP's doesn't tbh. I wouldn't push it, but I'd keep an eye on it, especially when school starts up. (I do agree fwiw with the poster who said lockdown has probably been a godsend for the introverts, I didn't mind it at all, and I saw a lot of my teens during online classes seemed more relaxed and "in the zone" as opposed to a constant FOMO which is a modern day scourge!)
I think we change too- I hate going out now, and as my job entails spending all day with lots of people (teenagers) the last thing I want to do in my free time is socialize. I wasn't like that when I was a teenager.
My friend has a daughter who has an overriding passion for something- as she hasn't met anybody with the same interest she does it on her own and it takes up all her time, and she is absolutely fine with it.
All kids are different and all find their happiness in different ways. Saying you don't care that you don't have friends and all you need is your mum and Netflix isn't one of them.