In fanfiction, Harry might use his knowledge of the secret passages in Hogwarts to hide from Dumbledore. He could also use Polyjuice Potion to change his appearance and blend in with other students or people in the wizarding world. Sometimes, he could even ask his friends to create distractions so that he can slip away and hide. For instance, Ron and Hermione could start a commotion in one part of the castle while Harry hides in a different, more secluded area.
Harry could use his connection with the magical creatures. For example, if he has befriended a Thestral, he could ride it to a remote location that Dumbledore would have a hard time finding. He might also use the magic of the Forbidden Forest to his advantage. There could be areas in the forest that are protected by ancient magic or that are simply difficult to access, and Harry could hide there. Additionally, he could use some advanced Occlumency techniques to block Dumbledore from finding him through Legilimency.
Maybe Harry is under the influence of some dark magic or a powerful enemy who has tricked him. This enemy could have planted false memories in Harry's mind about Dumbledore. So, Harry, believing these false memories to be real, starts to expose Dumbledore as a villain based on these false recollections.
One possible reason could be that Harry has discovered something about himself or his past that he thinks Dumbledore might not approve of or might try to stop him from exploring further. For example, if he found out some dark magic connection in his family history that he wants to understand on his own without Dumbledore interfering.
In the fanfiction, Snape could protect Harry from Dumbledore by using his skills in potions. For example, he might create a potion that hides Harry's magical signature from Dumbledore's detection. Or he could use his knowledge of the Dark Arts to counter any spells or charms that Dumbledore might use to keep tabs on Harry. Snape is very intelligent and resourceful, so he could find various ways to physically and magically shield Harry from Dumbledore.
One reason could be fear. Maybe Harry discovers something about Dumbledore in the fanfiction that makes him scared, like a hidden agenda. Another reason might be to protect Dumbledore. Harry could think that by hiding from him, he is keeping Dumbledore away from some sort of danger that is related to Harry himself. Also, it could be due to a misunderstanding. Harry might misinterpret something Dumbledore does or says, and as a result, decides to hide from him.
Dumbledore, as Harry's guardian in the fanfiction, would probably use his influence in the wizarding world. He could make sure that Harry is taught by the best teachers at Hogwarts. He'd also be there to offer advice and guidance, especially when Harry faces challenges like dealing with Voldemort or other dark forces. For example, he might teach Harry some advanced defensive magic privately to better protect himself.
Maybe he gets help from his friends. For example, Ron and Hermione could come up with a plan. They might send him a magical object that can help him escape, like a flying broomstick that he can use to fly away from the Dursleys' house without being noticed.
The relationship would become very strained. Harry's rejection would likely make Dumbledore re - evaluate his actions and how he has interacted with Harry. Dumbledore might be shocked at first, since he probably thought Harry was on the same page as him most of the time.
As the story progresses, Dumbledore might try to make amends. He could start revealing some of his secrets to Harry in an attempt to regain his trust. Harry, on the other hand, would be hesitant at first but gradually start to listen and understand Dumbledore's reasons.
Harry might initially be confused. He has always looked up to Dumbledore, so when he realizes Dumbledore is trying to control him, he could start to question everything he thought he knew about their relationship. He may become more rebellious as a result, trying to break free from Dumbledore's influence and make his own decisions.
He might give Harry detention. Harry could be made to clean the trophies in the trophy room or help Hagrid with some difficult tasks in the Forbidden Forest under strict supervision.