I think it’s fairly well established that if you drew a graph with number of transitioning people on Y and age on X you’d see peaks in adolescence for girls and middle age for men.
Might the simplest explanation be that puberty is a shock/big deal/massive change for girls - especially with perils, etc - more it is for boys On average, nabalt, etc). They want to opt out
Whereas for men that shock (etc) seems to come later and be connected to fatherhood?
Just a simple thought. But it’s amazing how much more easily you can think about it and sympathise if you start from what sex people actually are.....