It could also be that Kakashi has made some decisions during the Chunin Exams that Naruto doesn't agree with. For example, Kakashi might have chosen someone else over Naruto for a particular mission or task during the exams, making Naruto feel unappreciated and resentful.
The interference of external forces. In fanfiction, there could be some hidden enemies or manipulators who are trying to make Naruto lose control during the Chunin Exams. They might be spreading false rumors about him or creating situations that are designed to break his spirit, such as framing him for cheating or something similar.
Perhaps in this fanfiction's universe, Naruto's goals and ideals are completely different from Kakashi and Sakura's. Naruto may be aiming for a more radical change in the ninja world, while Kakashi and Sakura are more conservative. Their differences could lead to Naruto developing a sense of hatred towards them as they constantly oppose his ideas.
One possible reason could be that Naruto feels abandoned. His father was not around during his childhood, and he had to face a lot of hardships alone. Growing up without a father figure, he might have developed resentment.
It could also be due to a misunderstanding. Kakashi might be keeping some secrets from Naruto, like information about his parents or some hidden power within him. Naruto, being curious and eager for answers, could misinterpret Kakashi's motives for secrecy as a sign of distrust or dislike, which then turns into hatred.
One possible reason could be the way he was treated as a child. He was ostracized and shunned by many villagers because of the Nine - Tails inside him. This constant rejection and coldness from the people around him might have led to his hatred in the fanfiction.
Perhaps an injury could cause him to quit. If he gets seriously hurt in one of the early rounds and realizes that continuing could lead to permanent damage or even death, Naruto might choose to step down. He's brave, but not foolish. He also has dreams of becoming Hokage and if he thinks that by continuing in the Chunin Exams in an injured state he could jeopardize his long - term goal, he would rather quit and live to fight another day.
Naruto's hatred could be a distraction. Instead of focusing on his opponents and the tasks at hand, he might be constantly thinking about Kakashi. This could cause him to make mistakes and not perform as well as he could have.
One possible reason could be a misunderstanding. Maybe his team made a decision without consulting him, which made him feel left out and thus led to hatred. For example, if they took on a mission without him, Naruto, who values being part of the team, might feel betrayed.
One possible reason could be the lack of presence of his parents. Growing up without them, he might feel abandoned. And as for Konoha, if he hates it, it could be due to the way he was treated as an outcast, despite being the son of important figures. Maybe the villagers' coldness towards him made him resent the village that didn't seem to protect him from that.
One possible reason could be that in the fanfiction's unique take, Naruto's family might have abandoned him in a cruel way. Maybe they left him alone in a dangerous situation which made him feel betrayed and thus led to his hatred.