Using “they” takes a bit to get used to, but I’m totally fluent with that now, thanks to fanfiction.
I can’t see why “nhw” couldn’t be used in the same way in Welsh.
Finnish nicely doesn’t have this kind of problem. We have had athro - athrawes distinction but I have never ever heard anyone use the femine form of any word. The femine forms are essentially died out from the current language.
Interestingly, if you do want to emphasize that it’s a woman you are talking about, the current language add the prefix “woman” to the work. So athro - “opettaja” and athrawes “naisopettaja” instead of the mostly archaic “opettajatar”. But the word “opettaja” is not giving any implication of the gender.