I think that only someone who is transgender could really enlighten you to the experience of being transgender and what transitioning meant to them / the purposse for their transition.

For my brother there is a strong dysphoria. His body at its most personal level is wrong. Having the breasts of a woman, or the inability to grow facial hair, are an affront to who he knows he is. His experience of his sexuality is masculine. His expression of himself is masculine. Transitioning with hormones, and maybe one day prosthetics, is what he needs to end the dysphoric experience of his own body and thereby his existence as an individual.

Other more superficial elements to his masculinity - such as the way he dresses or gets his hair cut - are the best he can do to present as the man he knows himself to be.

I believe that as he transitions, his expression of himself as a man on the superficial level will change into a more personal expression, rather than an attempt to alter the gender (and with it, its norms) others have assigned to him in order to be validated.

One thing I do know is that my brother's journey to coming to terms with his masculinity and my own mirror each other in more ways than one. Our struggles with what masculinity meant were near identical. In particular the disconnection with masculine gender norms and hyper-masculine culture. And likewise what femininity entailed. For the both of us, though with profoundly different experiences of our own bodies, the conclusion was that gender lacks meaningful substance beyond the personal. Its social element is a practice is cognitive dissonance and contradiction.

Having that intimate relation to the experience of my brother thwarts any notion that this is a capitulation to gender norms on his part.

Of course this is only an anecdote, so take my perspective with some salt.