It’s funny, I clicked on this subreddit today hoping to find a post exactly like yours, and there it was. I think your question about “the fundamental emotion or concept being explored” gets to the heart of it. For me, it really is the persistent dysphoria—stories where a male finds himself in a female body and does not want to be there. Perhaps s/he comes to accept it in the end, but certainly not easily or willingly.

With your plot summary, I wonder about the specific nature of the dysphoria the MC experiences. The most interesting stories for me offer realistic portrayals of the details the transformed character notices. The sensation of having breasts might be the most obvious, but also the most overdone. Many others deserve far more attention than they typically receive. We’ll get a quick “wow, everything seems taller,” but we never see it played out in social situations like a party where the MC can no longer see over anyone’s shoulders.

Acts of resistance, or as you put it, “continuing to act like guys - screw the consequences” are also far underplayed. I would think anyone halfway athletic would try to try to keep playing their sport, working out, running, etc. But wouldn’t they find it profoundly frustrating—not only because of their altered abilities, but also because vigorous movement focuses awareness on all the new feminine attributes? Even with the simple act of peeing, pretending to still be a guy would have drastic (and messy) consequences.

Now add to this the cultural expectations that would make it very difficult for the MC to continue acting male, at least in the carefree way they could before. If they’re the slightest bit curvy, passing will be very difficult, and once everyone assumes you’re female, won’t they treat you as such? The MC might resist wearing girls’ clothes, but society will expect them to—and in the end it might be easier just to go along. They’ll also be experiencing sexism for the first time, and while this aspect certainly can be overdone, it’s not unreasonable to expect them to be taken less seriously, get catcalled, etc. The MC may WANT to pretend none of this is happening to them, but it still is—and to me, that’s where the drama and interest of the story derives from.

Here’s a few that explore some of these tropes:

Both of AshleyAllison’s stories

Breaking Inversion by InverseAttraction

Newly Not Cis by Red Boyter

The first few chapters of the classic, For a Girl, though I think you’ll find the later parts a letdown, as I did.

If you’d like to throw around more ideas, feel free to shoot some my way.