I think I can see the point of confusion- the reason for illustrating physical sex as a spectrum is that it’s easier to lay out the concept of gender identity as an analogue.
It’s also possible that gender identity is structural but brains are complicated and linking mechanisms to behavior is hairy.
I hope people struggling with Cluster B personality disorders get the help they need. However, I’m too traumatized by abuse from people with these disorders to engage with anyone who exhibits the associated toxic behaviors.