Non-binary as a term probably did not exist, but non-binary as an experience definitely did. People living outside of the gender binary is for sure not a new phenomenon.
And I agree, some of the points they made were a little clunky or really toeing the line of anachronistic, but to me it felt like everything set up a bigger plot point or song or both. So I was ok with a 2022 musical being a little 2022.