You’ve got that very wrong I’m afraid. I don’t know where you got your definition of gender critical from?
Gender critical beliefs are explicitly against gendered stereotypes.
We believe (know) that there are two sexes, it’s a reproductive function, male/female, it’s just biology.
Gender expression can be what you like. Girls who have short hair/don’t like pink/like maths are just as much girls as those who want to play with make up all day. Boys who like dolls/hate football/ like glitter pens and rainbows are just as much boys as those who like cars and climbing trees.
Your likes/dislikes hobbies, skills and interests do not define if you are a boy/girl or woman/man.
A woman can be whatever she wants, and a man can be whatever he wants. That is a wonderful thing that we should celebrate. But a person’s sex will not change.
Trans activists seems to believe that it is outward expression and likes/dislikes that makes you a man or a woman. To GC people this seems incredibly stereotyped and limiting. And quite offensive; long hair and lipstick are not what make a woman; we are infinitely richer and more variable and deeper and interesting. All that connects us is our biology and shared experience of growing up female in a world where we are smaller and weaker than the other sex, and a huge amount flows from that.
So GC people believe that where services and facilities are separated by sex, it is because of our sexed bodies. Female people are vulnerable to assault by male people. Statistically speaking. We also have to deal with child-bearing (disadvantage in the workplace).
We believe that dividing things by sex (where division is necessary at all) should NOT be replaced with dividing things by “gender identity”.
I love maths and woodwork and driving cars. But that doesn’t make me a man. That’s just gender stereotypes of which I am critical.