I wasn't going to contribute to this discussion, but since I spent my time reading all 123 chapters I might as well write out my thoughts. I was majorly disappointed with the ending, to me it felt like the author was told she had to end the manga and she just said "f it" and gave us THIS for an ending. I feel like all of the character development amassed to nothing.
Some things that particularly irritated me was the fact that Nitori was the one who decided to transition in the end rather than Yoshino. In the way I interpreted things, I would've thought it would be the opposite outcome. One of the reasons I thought this was because Yoshino had always openly presented themselves as masculine (although it is easier for a girl to wear masculine attire rather than a male in female attire), and Nitori was less confident going out in female clothes. Most importantly though was how Nitori was evidently comfortable with his body and genitals, talking about how much he loves masturbation at the end, which is nonsensical if he really has gender dysphoria.
Also, although I understand in a way since they were together for so long, it feels almost lazy to me that Anna ended up with Nitori. She had broken up with him once because he wasn't 'manly' while he was in middle school* (I believe), so it's saddening that instead of coming up with a new pairing Nitori might've had a brighter future with it just stayed the same with Anna and Nitori. I can view them as friends, but nothing more. I just don't see it.