Someone is using my PS Account on another console

Hey. I really need someone who can help me. I have a PS5 and my Account has the 2F Authentication activated, but when I open my app I see that someone is playing Fortnite and GTA 5 on another PS5 with my account while I neither own or play those games at all. I changed my Mail and PW multiple times and deactivated all consoles and for a time I got a warning on my phone that someone is trying to use my account on another console and if I want to decline the login. But somehow they still managed to do it.

I was in contact with the PS Support but they were not at all able to help me. They told me that my profile isn't used on any other console and that I have to activate the 2F which I already did!

I don't know what to do and I don't wanna delete my account because I have so many games on there but I don't even get notified anymore if someone wants to use my account. It's getting on my fucking nerves because they use my PS Plus. I never entered any bank info so they cannot buy anything except with PS Cards.

Every help is highly appreciated.