Look, regarding Mc... Yeah, he's very infuriating and he creates a lot of his own troubles, I would say everyone is pretty normal but him (girls fall for jerks all the time) but what he's doing for the little sister isn't bad here... You have to take damage sometimes to learn and to move on, if there's one character we'll written that has growth through the novel, it's probably her. (ironically, also fake Mc but much later)
Regarding the spoilers about the novel being meta... Yeah, everything is about how the "plot" makes everything happen and if the characters are under its influence or not