Deeply flawed? Equally certain.
The entirety of your arguments rests on semantic circularity and a white, western point of view. Technicalities and privilege. And from these dubious cornerstones you’re led by the nose to the nebulous conclusion that "A productive and virtuous life with love, friendship, and an appreciation of truth and beauty is authenticity enough." I'd respectfully point out that 'gender identity' as ill-defined as you believe it to be, is still a better basis for legal protections that your empty platitudes.
You examples are ill-fitting and easily refuted. Oh so you don't 'feel tall' or 'bald' I suspect you'd be far more conscious of those innate traits were you subject to discrimination and potential physical danger because of them.
You cite two outlier trans women as 'proof' that a female core gender identity is not requisite to one identifying as such. Pfft. The exceptions prove the rule is wrong?! Dear gods man. So much for Occam’s razor. And this alongside your invocation of parsimony!
I shudder at the mental contortions you've allowed yourself in your search for confirmation of your prejudices. I shudder more that your 'conclusion' amounts to nothing more than an admonition that trans folx live virtuous lives and it'll all be fine.