i love slow burn but….

This is actually painful and furstrating to see as I really liked the premise of Monochrome Rumor. I let it marinate like for 3 months in hope the main story will progress a bit, but as you see there's no progression at all. The presence of the idol routine was already there from the start and it wasn't a problem because we need to know how Hajin/new Sihyeon will adapt to his new life as an idol, but these chapters about the idol stuff looked already disconnected to the main story.
For exemple, the other members of the group were like strangers to the OG Sihyeon; did they ever tried to understand him or looked at his problems? He was always so depressed like he could be suicidal, where were they? But now that it's the reincarnated Sihyeon, they're all over him (??).
I get they're worried for him, but if you were so worried, couldn't you have tried better, boys? If it's not a plot hole then what is this? And this is not the only one.

I don't know why the author made so much efforts into writing the background of the plot, just to let it get overtaken by the idol thing.
Did they want to write a dark story, psychological? Or did they want to write some fluffly slice of life...? (??) You can't have both stuffed in a story without connecting the 2 universes.
Considering the OG Sihyeon past, this is terrible that MC is not trying to understand better his body's owner problems and what actually lead this latter to the accident. Because Hajin is a strong protagonist I had so much hope he'll somehow avenge the weak Sihyeon etc, but even if he doesn't want to, to just existing now and sleep like that is so out of his character and context. What the author actually want to do? (╯°Д °)╯╧╧ This story gives me headaches and makes me sad.
I just have now fragments of the main story and don't want to go through all the idol stuff to see if there're some clues I might've missed...