I studied Judith Butler in the 90s – I had a copy of Bodies that Matter and also read Gender Trouble. Though I hadn’t read her work since then and didn’t realise she was now a ‘they / them’. I could get used to those pronouns, just like I can get used to Mx. What I get confused over, is whether someone like Eddie Izzard is now a woman, and the practicalities of what spaces they have access to. It’s almost like we need gender-neutral toilets and changing facilities ALONGSIDE those for male and female. Then Eddie Izzard could go there.
I might have mentioned this before but in German job ads, I have sometimes seen m/f/d, where ‘d’ is for ‘divers’ (I think anyway). So the non-binary and trans could go into the third category to all intents and purposes, including legal. Because if social gender supersedes sex then non-binary eventually should also be legally recognised.
Alternatively, you could go back to biological categories for pragmatic reasons (m/f toilets etc.), while society becomes more permissive towards transvestism (socially presenting as a different gender but each having distinct sex-based rights).