In the little town she allowed her grief to utterly consume her. She put the town in a hex so that it couldn't be accessed by the rest of the world, without great cost, and used everyone as her personal playthings. Wanda even made a replica of Vision who has independence unlike the rest of the town's citizens.
Over the course of the show Wanda came to accept that Vision is dead and what she was doing is wrong. So she frees the citizens of Westview and flies off to a remote area. That was a good end to her character arc and put her back on the path of a hero.
Then came Doctor Strange in the Multiverse of Madness that seemed to undo Wanda's character arc just so she could be the villain of the movie.