My American boss used to use the term Becky. But yeah, there's middle-aged woman being assertive (and good on her) and then there's Karen behaviour. I like discussion on this kind of thing because it talks about the large areas of what is reasonable behaviour and what is not.
I heard they call Karens Becky before. This kind of behavior is becoming popular/viral where I am, we just don't have a name for them yet.