Well, Harry might outsmart Dumbledore by using his unique understanding of the magical world in ways Dumbledore doesn't expect. For example, Harry has a more direct experience with some dark magic items due to his encounters with Voldemort. He could use this knowledge to make decisions that seem counter - intuitive to Dumbledore but are actually more effective in a particular situation.
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.
One possible reason could be that Harry breaks school rules in the fanfiction. For example, if he ventures into the Forbidden Forest without permission. Dumbledore is strict about the safety of students and such disobedience might lead to punishment.
For Harry, his friends like Ron and Hermione are likely to be his allies. They've always been by his side through thick and thin in the original series, so it's natural for them to support Harry in a confrontation with Dumbledore. Neville could also be an ally, given his growth and courage shown in the books.
In Harry Potter fanfiction, a male professor can play various roles. For example, he could be a mentor figure like Dumbledore, guiding the young wizards. He might also be a villainous professor, creating obstacles for the main characters. Some fanfictions might explore a male professor's backstory, his relationship with other characters in the wizarding world, or his own magical research and discoveries.
Well, it might be a fanfic where a new dark wizard emerges with a unique power to manipulate memories, and they target Dumbledore's memories of Harry Potter. Or it could be a story where Dumbledore gets caught in a complex web of magical experiments gone awry, leading to this memory loss.
One key event could be a situation where Harry discovers a hidden magical ability that Dumbledore was unaware of. This new - found ability allows Harry to approach a problem in a different way and outwit Dumbledore. For example, if Harry discovers a way to communicate with magical creatures in a more profound way than Dumbledore ever thought possible.
It might make Harry more confident. With Dumbledore's training, Harry gains more knowledge and skills, which gives him the confidence to face challenges.
It could be that Harry finds out about Dumbledore's secrets regarding the Deathly Hallows. If Harry thinks Dumbledore was more interested in the Hallows for his own purposes rather than for the greater good, it might make him hate Dumbledore.
Well, in this fanfiction, Harry might be a professor because of his extensive knowledge and experience in magic. He could be teaching younger students and sharing his wisdom.