It's an interesting drama based on the reality of how the kpop industry works. I came to this drama because I know OnlyOneOf as a group. Because of that I thought this drama would be really cringe to watch (they are rookie actors and have no experience in acting), but I was honestly surprised with the overall quality. It's a low budget drama, but it's ok in terms of korean BL dramas.
The story was compressed in 8 episodes of 15 minutes what made it feel too rushed. Things were happening too quickly so they used a lot of flashbacks to tell the story. It was smart in storytelling, but as a viewer it feels like you are being attacked with a lot of information from all sides. But that's my only complaint about the script per se. The adaptation from the webtoon was well done and I honestly think it was WAY more sensitive about the topic than the original work.

Like I said before, they have no experience in acting so I wasn't expecting much, but some of them really have a lot of potential. Hyunbin is an annoying, but really charismatic villain. You can know the actor for a villain is good when you feel angry the moment he shows up. In the terms of acting, I think KB was the best one. He looked evil for real. Eden and Jihoon were good as main characters. Eden did look innocent, but not dumb (so common in BL) and Jihoon was an experienced sunbae, but he wasn't an annoyingly cold character for no reason (also common in BL). The characters were well balanced and the actors did well. Nine did a specially greater work in the scenes he was angry which seems a funny thing to actually happen. I don't know if he rehearsed those parts more or if it was fun to him to manhandle KB, as he's the youngest and KB is the oldest.
Jay was an adorable character and I hope to see more characters like him in BL. A character that will back off after hearing a "no". As any BL fan know, characters in Bl usually thinks a "no" means a "try harder".

About the whole plot, I GET that some people will get angry with it. K-pop fans will probably get kinda pissed too. The plot says "the K-pop industry uses gay fanservice to please fans". But is it a lie? EVERY K-pop group will do that and that's set by their company. If you read that and thought "those two (any ship name) don't do that because thy are really close for real", then you know the industry made it work and it already got you. Yes, most idols from same group are probably close, but the fanservice IS REAL, so please don't fool yourself. They will do things on stage, they will lovingly look at each other, they will hug and hold hands and do all that and 80% of the time all this is for show.

All that being said, the whole plot of this is great. It shows how the industry works and how fans respond to it. Now imagine this: companies make their idols do fanservice and among them there are straight people, but there will be queer people too. Imagine working in a place that forces you to PRETEND to be gay as a job, but WON'T ACCEPT you if you ever come out. In this story every main character is canonically queer. Eden even represent a queer kid growing up with a heteronormalized mindset. His first love was a boy, but he never really accepted that part of himself until adulthood.
In the story there's even a part that one of the trainees say there are rumors about Eden and Jihoon as a real couple and he make it sound like a bad thing (as if they weren't pretending to be gay to begin with). In a place like South Korea it' ok if you pretend to be gay, but it's not ok for you to be actually gay. The story is kinda fluffly and soft, but there's a real critique behind it if you pay attention.