Can someone explain me how exactly is ONIMAI a trans manga/anime?

(I'm gonna use 'he' for the old Mahiro and 'she' for the transformed Mahiro) First of all, I don't mean to be passive aggressive here, despite this biased title saying otherwise, I just want to know the opnion of other people and see if someone can convince me ONIMAI is a trans manga/anime. I've already saw people saying that Mahiro felt more leaned to girls things when he was a man, some that say Mahiro feels happier as a girl than as a man, and even saw a comment about the manga being the ultimate fever dream of trans women who transitioned at adulthood and wished they could have lived as girls during school. Well, I've watched the anime and read the whole manga two times, and I'm pretty sure it's never mentioned that Mahiro have ever had any matter with his gender before the transformation, Mahiro being happier now it's simply because now she has friends and lives better, she would feel the same if it happend while she was a man or was deaged but kept being male, and... I'm not a trans woman, I'm an agender and I understood it relatively early, so I can't discuss about this last one. I personaly can't see Mahiro as a trans girl for the simple fact that she (as far as I know) never felt like it before being transformed and even now doesn't feel like a girl and fights not to stop being a male. I can't and I won't judge or argue with anyone for what they think about the manga, but, as a trans person myself, when I see someone saying Mahiro is trans, or that it's a trans manga/anime, I just can't help but think "Guys, are you really sure this manga about a man who is turned against his will into a little girl and, even though he wanted to return to being a man from the begining, feels obligated to continue transformed and play he is a girl afraid of losing his friends, is, if it is even doing that, doing a good representation of a trans person and of what it is being trans?".