I kinda get what you're saying. I don't think Jaekyung's character development was as rushed as people are making it seem like, but I think the ending was definitely rushed for the sake of just ending the main story before it dragged on too long.
Like, we had this big plot climax (ew) all at once where conflict popped up left, right, and center. It was gearing up to be very serious, yet it gets wrapped up almost immediately.
I think that's what most people are upset about. It's not really the characters themselves, but it's just the way the story ended. It seems so... blah, if that makes sense.
They get their happy ending, which I'm glad to see, but I wish it would've played out a little differently. Kim Dan getting stabbed and Jaekyung realizing it was the... bald guy... (omg what is his name lol) who planned it just went by sooo fast compared to how slow the rest of the story was. The pacing was real bad, and that's the issue. The ending felt so "oh, boy. What do I put here to actually end this thing? Oh well, just put whatever and make it sappy."
That's not to say I still didn't kind of enjoy it? Like, it was okay. I'm not gonna hate on it, I've been waiting years to see Jinx's end lol.
To be honest I felt like everyone acted in character, so I thought it wasn’t too rushed, I do kinda get how it could feel like it’s not ended properly like somehow there seems to be things left to resolve. Hopefully that makes sense I’m tired as
I've read a lot about how readers said they feel like it's rushed but I don't see it like that.
Jaekyung's past actions is unforgivable but people change, he also realizes this as the story progresses.
As for Kim Dan, his lack of confidence from the start was not really resolved but the ending shows that there is a room for improvement regardingt this.
I hope I'm making sense Please don't clock me, I'm just saying what I had thought about the ending of this story