The author has made the same mistake One Punch Man has made: Making the MC so overwhelmingly strong that the only option is to remove them from their own story.
One Punch Man was a good gimmick, but it became clear quickly that Saitama had to be pushed aside in order to keep the story tense. Similarly, JinWoo has to "decide" to stay out of the fights (until the climax) in order to make the story interesting. He's basically an untouchable god at this point, popping in to solve problems when things have become sufficiently hopeless.
In other words, this shit is getting boring because the author made the mistake of making the MC too strong. Just like One Punch Man.