to complement the posts above i would like to briefly outline a point that helps understand why mainstream feminist discourse (but not some transfeminist discourse) fails to address gender diversity and the role that GNC/transmascs play in patriarchy.
(from there one CW crude transphobia and slurs)
Bluntly, patriarchy splits the world into exploiter and womb. The blur around this line, where you find trans people, GNC folks, etc? Patriarchy tries to remedy it really fucking hard. It contains the defective, and the faggots.
Someone failing to be a reproductive mother? Defective. Sterile cis women, trans men who "cut their breasts" and "remove their wombs" are routinely called defective and great effort is done to try and "bring them back" to femininity and reproduction. This is one common source of transphobia for transmascs: being brought back to the fate of someone giving birth, something feminine and exploitable. Patriarchy will try to the bitter end to extract reproduction out of people who can bear kids.
Someone failing to uphold the patriarchal hold that men have on society? A pariah. A disgusting "thing". A (insert slur here). If you fail to uphold patriarchy unto other men and women, you get laughed at, called slurs and unmanly and stuff. But if you get conditioned and traumatized enough, you can be a good man too. If you renounce your role as a man enough you permanently lose the right to the privileges. You do not gain the right to be in the "womb" category either, because you can't be exploited for reproductive purposes. Sexual purposes at best if it's in a way that a cis man can fetishize.
And here's the kicker: if you're blurring the lines of gender and sex, on an individual level, i can guarantee you patriarchy gives zero shits. Its collective eye will look at you, judge where and how you failed, and will either beat you back where it thinks you belong or permanently banish you from belonging to either box. Society WILL force you into either box or it will violently prevent you from being in either. This underpins a lot of the seemingly weird obsession transphobes have with genitals, chromosomes, etc. They MUST uphold the categories of womb and exploiter, and crush whatever else doesn't fit.
