I think the bigger problem is that although K-Pop and Mirror are both extraordinarily long stories, the actual visual feminization of each of the main characters couldn't be more sudden/jarring.
In K-Pop between Chapters 4 and 5 the main character goes from looking very male to suddenly 100% beautiful female entirely off-screen. Then in both stories each protagonist gets surgeries off-screen which makes them each look like totally different characters.
Surely the point of having so many panels in a story is that we get to see visually the gradual transformation of a character that is recognisably the same person from one panel to the next. Otherwise what's the point?
I completely agree. Even in "Need for Speed," this was a deeply disappointing moment: The main character rounds out, becomes this cute trans person, and BAM! A page flip, and it's just a different character with a different face.
But this is generally the problem with almost all such long stories. I've already mentioned this, but I'll repeat it. When the changes happen in the first third or quarter of the story, the rest of the time (and in Melissa's case, it's several years) you just watch a very shy and hesitant chick who, for some reason, is happily ready to suck anyone's dick. Only in the sex scenes do you remember that this is a trans story. And even then, unless the author decided to perform the surgery "there."
This completely defeats the purpose of a transgender story—about transformation. The author apparently always wants to show off some amazing plot, but of course, it doesn't work because, ultimately, the author is a trans artist first and foremost, not a screenwriter. It's also impossible to trace any internal breakdowns or experiences, as all the characters are equally vulnerable, hysterical, and susceptible to minimal and blunt manipulation. Strictly speaking, they're all identical. Again, because the author is first and foremost an artist, not a writer.
For short stories of 8-12 panels, this is all forgivable, of course, because you get a concentrated vibe, and with different stories, there are also different settings and personas (here a maid, there a secretary, etc.). But you're watching "this" with half an eye, almost waiting for it to end so you can get to the first third or quarter of the new story.