I'm not going to read the novel, so I'm not sure if my criticisms apply to only the show or also its source material.

I'll start by saying there were many scenes that were well written and well acted. The show is much better than average BL in general. I loved the side couple.

My criticism comes in where i kept feeling that plot or character foreshadowing was going one way only for it to go a completely different way. Sometimes that can be a good thing if it's a certain genre. But it's the foreshadowing that makes the progress of story and characters feel more satisfying. So a good emotional romantic plot can't thrive so much with too many unexpected turns.

As a writer myself I always (on reflex) try to guess characters motives and goals and what kinds of things it would take to change a character's feelings.

The character of Khai was a well written jerk that had a solid characterization even if it was a cliche.

I think the problem came in that his jerk-ness was made so solid and consistent that there were so few options that felt like a believable way to make him fall for the lead character.

I spent half the show trying to figure out if Khai was indeed half of the main couple or if he was merely the object of desire which would result in the MC moving on and finding a healthy relationship because of his crush trainwreck.

I don't know if maybe the characterization evolved more naturally in the novel, but Khai's transformation was a little too sudden for how bad he was in the beginning. I don't like pairings where the success of the relationship hinges on one character's transformation. It's too easy to feel unnatural.

The side couple had a little more consistent buildup and characterization, but there were still confusing parts where you feel like they were suddenly replaced with a different couple and their one-on-one scenes together were for no reason. They had the better story, even if the show forgot about them multiple episodes in a row.

Even if i feel like i could've written the story better in many different places, it kept my interest enough for me to want to finish it quickly.

It also didn't rely on basic tropes with the same conflict and outcome. You think the same tired scenario will play out like every other BL, but then it won't. That was refreshing.