there wasnt really any development towards their relationship at all? also isn't this more just like a story about a trans girl rather than a crossdresser (use of "coming out" and only being seen cross-dressing)
I mean, gender presentation isn't the same as gender identity. A lot of people who were referred to as "transvestites" in my childhood would be recognised as "transgender" now, sure, but a small portion of them would indeed just be male-identifying, female-presenting, no further explanation needed.
I will admit it does feel pretty trans here though with Haruno constantly in a quest for greater femininity, and referred to more and more as a 'girl' in one way or another.
Complicating matters, based on the author's other works and what it was spun off of, it seems to be a comedy written explicitly for "crossdressing" enjoyers. It was published in Japan back in 2013 when popular perceptions were a bit different (although Japan is still broadly conservative still). Indeed in one passing 'gag' we see the at-first supposedly "accepting" protagonist questioning "why" the love interest's family is so supportive of the crossdressing as if that's irresponsible of them—this is hardly a manga written with a trans-friendly worldview, arguably to the point of being implicitly transphobic (although not necessarily with any malice). As in a lot of cross-dressing stuff, it feels like we're tacitly encouraged to consider the 'crossdresser' as a girl
only as a fantasy which leaves us with a complex (and reasonably toxic) set of implications.
So: Do we go by "what the author seemingly thought they were writing", even if that worldview is potentially degrading? Do we go by "what we think this character, if they were an actual person, would most likely choose for themself if given the choices we give people nowadays?" even if tagging it that way (not that we even have the relevant tags) would vastly disappoint any reader looking for any sort of trans narrative?
(Also: "Coming out" is going to have been the translator's choice of phrasing, surely, so I wouldn't feel confident using that in decoding subtleties there without diving into the original Japanese. I mean this is a translation that uses "trap" as a term so we're already necessarily talking about a translation that, technical skill aside, is demonstrably neither particularly sensitive nor overly-concerned about being tone-faithful to the original text...)