I think people here give too little credits to the author. For one, they explored gender change issues previously, in a darker way (that got their series cancelled) and this one added more comedy to make it less "depressing", but the themes are still there.
And they obviously did their homework, because the way they describe the surgery, etc, means they documented themselves on it quite a bit.
So, what is this manga about? It's about the journey of "former girls" in the context of a near-future Japan society. That's all.
From the context, you can understand that the disorder is something recent (Saya's brother still remember GB manga being a thing but having been cancelled) and that probably Japan laws didn't change that much (it's a conservative country). So, to be considered a woman in the family register, which is Japan specific, you have to not have a dick and be unable to have a child (though that may have changed in recent years). And since Rinko has a dick now, they would be considered a man in the family register. Call Japan a backward country if you want, but that's the way it is.
So, what the author does is presenting Rinko's pov, and probably other former girls in the future) and how it wrecks havoc in her life and in her relationships. The mother is here to represent the "conservative" side (though she's not against eventual SRS) and the father represents the "carefree" side, without much thoughts about the future but just witnesses the immediate pain of Rinko. We have the same opposition between Saya and Subaru, with one being like "just go for it" and the other being "hold your horses".
Now, Rinko got "magically" changed into a boy and now gets hardons when confronted with the female body.
I saw some comments that the author attributed this to the hormones. It's not really true. It's stated in a previous chapter that Rinko "always liked boobs". Which is a hint the author put to show that the sexual preferences of Rinko were not that clear cut, even before the change, but maybe the change just magnified that aspect. She was romantically attracted to Yuuki senpai and still is (?), but was she sexually attracted to him? It's not clear. But in the present, he just does nothing for Rinko's dick. That may have been comphet though, like before it was logical and normal for Rinko to think that liking Yuuki equates wanting to date him and be his girl, but with the change it's not clear anymore. Rinko may be bisexual OR may have only been attracted sexually to girls before without really thinking deeply about it.
What about the lack of talk about puberty blockers then? I doubt the author doesn't know about them, since they obviously did their research. But remember, it's a manga and the goal of the author is not necessarily to describe Rinko's journey to go back to being a girl. It's a mix of comedy and drama about former girls (plural) and putting Rinko on puberty blockers right off the bat would probably get in the way of what the author intends for the future. This is not a manga about the journey of a trans girl, which would get into the details of the transition of the MC (there are other manga that do that), it's about various characters and how they deal with the sudden change. Maybe some other character will be on puberty blockers in the future and explain what that entails, we don't know.
Now that's out of the way, there are still many questions and it'll be up to Rinko, who will interact with the other "former girls", to find answers.
There are various ways this manga can go :
- Rinko decides to go back to being a girl, after weighing her options carefully and goes for the surgery, etc.
- Rinko accepts the new body and eventually adapts. Maybe Yuuki's own journey will play a role in that?
- Rinko changes back magically again
But what is sure is that the mangaka will introduce new characters and new challenges for Rinko and explore gender issues and will not cut her journey short by putting her on puberty blockers and go in Thailand. This is not the manga you're looking for.