and a brain (gender) that didn’t match.
I have sympathy for your struggles with anxiety, but I have the right to disagree with your views on gender. I believe that gender is a social construct that does women great harm. I do not believe that my breasts dictate how my brain feels, or that there is a right or wrong brain for male and female people.
Now imagine celebrating and applauding a person who would mock someone for something that happens before they are even born.
You have not been mocked, and certainly not by JK Rowling who has only commented on sex.
You have a believe that female and male brains are intrinsically different. I don't. You have a right to express that view. You do not have the right to insist that everyone else agrees with your view.
Can you not see that by insisting that you are non binary and that other people have a feminine gender, you are forcing gender on others?