It’s honestly really hard to communicate because your thinking is so ingrained within a particular system of ideas, that I don’t subscribe to, but you are assuming is universal.
When I was talking about the provision of facilities for women, I meant eg loos with signage with the words - “woman”, “female”, “symbol” . I don’t know how to be clearer about that.
There facilities are mostly used by women registered female at birth. they are also sometimes used by trans women.
On the question about sex and gender- It’s complex. But do I think the gender critical framework for understanding the two constructs as distinct and mapping on to a binary : real/ fictional, biological/ ideological framework is helpful or meaningful? No.