Isn't Dumbledore's job as Hogwarts Headmaster a position of power?

Isn't Dumbledore's job as Hogwarts Headmaster a position of power?

The death of Dumbledore's sister Ariana was due to the duel with him and their brother Aberforth against Grindelwald and also Dumbledore wanting power and wanting wizards to rule the world and have Muggles enslaved.

His sister's death is also what caused Dumbledore to always reject offers to be Minister of Magic, since it was an offer of power.

But isn't Dumbledore's job as Headmaster of Hogwarts also a position of power? If so, why have this job when remembering that tragic moment in his past?