I get what you mean but I think Kisub had feeling for him from the start and it was more about him realising what they were ( the scene where Kisub was drunk kinda hints to that) and Ithink thats also why he wanted to live with Jinwoo. The series isn’t that fleshed imo but it’s fun and cute so idc haha.
Please go read the manhwa this is adapted from!! It is a masterpiece and this feels more like an insult compared to it. It just doesn’t work as live action.