Hard to say. Not even Thanos could do it in Endgame. She almost ripped him apart (although he/his past self did deserve it for murdering Vision).

Black Bolt could kill her but Reed was so stupid who said to Wanda his powers. Also Captain Marvel, Galactus, Ghost Rider and Thor (maybe) could defeat her. Thanos actually could win if he knew Wanda's powers EDIT: (MAYBE)...