To be fair, Peter is stuck in a vortex of emotional conflict. He wants to do right by his friend who he feels like he let down. And what she wanted was revenge exacted against someone who did nothing to her. He knows that but he also knows that she killed herself over that idea after he cut off their friendship. He also seems to know that the actual friendship they had was pretty bad.
Then you add to the mix his highschool gay panic that he never dealt with. The fact that he feels guilty for having never admitted to his friend that he also had a crush on the same guy. He feels guilty for lying to Woohyeon, he feels responsible for Jennie's death, he's in the closet, and he has no support system. Add all that to the fact that he might just be the meekest mildest person ever. He really can't develop more until he addresses any one of his very sad issues.
Truly, his mom should have put him in therapy. But him being the way he is is also a huge character foil to Woohyeon and I kind of love it. I love watching him try and fail at being vengeful because he really just doesn't have it in him. He just wants to feel better on the inside and he's stuck.
you bring up a lot of good points, especially about his inner turmoil. i hope we explore more of that in the next couple of chapters cuz that would really flesh out his character, and like i said, i just really want to see more growth. idk i feel like we're kinda stuck rn but that might just be because peter has been stuck in that room for the last few chapters lol
i just wish the mc was smarter and more cunning. i think the revenge plot is interesting (even if i think the reason behind it couldve been better) but inseob just never seemed like someone who could pull it off. i think the problem is that the author tries too hard keep the "innocent and naive mc" trope--to the detriment of the story--but i thought itd be cool if we saw him develop, either in the direction of regretting his plan or going 100% revenge mode (which i wouldve preferred). but instead inseobs character has stayed the same and its gotten frustrating when hes paired against someone whos willing to do whatever (even murder) to get what he wants. idk i just wish they were on more equal footing (im terms of ability)