This is an absolute must watch imo. Yoon chan young is amazing young talented actor with great potential to be star, I'm sure if he goes like this he will be one day. The show is very well written, probably one of the few where bullying is portrayed best it can, the character building is amazing too. Ik many bl fans are upset that it is a bromance and some toxic bl fans are boycotting it or leaving bad rating out of spite (seriously sometimes bl fans can be too much) but give it a chance you'll not regret it.
I also wanted to add that they didn't redeem the bully by showing some sad story about his past but he actually worked for his redemption and felt guilty for what he did to the victim.