So this is some Gone Girl level of messed up.
I'm under the impression that this was just intended to be a drama BL but the whole thing ended up as a really warped psychological horror. It's the sincerity that makes this series so disturbing. There are lots of psychological thrillers on this site (even BL ones) but this story has completely unintentionally become one.
There are all these moments that are supposed to 'oh no! misunderstanding!' but end up reading like a tragedy because of how damaged everyone is by the end. IDK if this is supposed to have a 'bad' ending or if it was supposed to be sweet because it's reeeally not.
I think this is a concept that would have worked best with a little more editing. Like I don't mind the doppelganger element, or the trans story-line, but in order to have been sweeter (I guess I want to say?) maybe the original GF should have just been a really bad breakup and Hyunwoo was just messed up because of that so he starts dating Jimin because she looks just like her. That would have made the whole 'blind date' more plausible. None of the other elements would have had to change (though I really would have softened that whole crazy stalker best-friend thing but you do you I guess). The subplot with the best-friend and the potential new lover could have also been a little more fleshed out.
Either way this was a really interesting read, if not just a bit disturbing.
Rant out.
Watching those numbers crawl up is so, so satisfying! Is this what a dating sim actually feels like? XD