An American woman I know was angry and referred to a gay couple as “queens”. I raised it, she is straight cis and says the word is fine in America. I’m in the UK and it’s not ok here unless you’re lgbt yourself (and even then plenty wouldn’t like it).
Can anyone advise?
It’s fine when used by someone who is queer.
It’s fine when used in a friendly manner (“Yas queen!” in response to someone’s enthusiasm for something).
It’s not fine when used as a slur, like in OP’s scenario.