It's worse in the comics. In the comics - her power goes out of control and she ends up killing Hawkeye and Vision. This drives her insane and she changes reality completely. When they figure it out and try to fix it, her brother gets killed, she snaps, and cancels mutants - basically does away with the mutant race - aka those who make up the X-men. She's then hand-waved as a villain, and allowed back into the Avengers.

And she's Magneto's daughter, then determined not to be, but a false mutant.

Scarlett Witch's arc in the comics is wonky and kind of bad. It's actually better in the MCU/television series.