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)...

@Paperinick but are we even sure black boat could’ve still disintegrated her? She was pretty confident in her powers in Multiverse of madness and probably could sense what his powers would be anyway and still would’ve been undefeated. The Scarlet which is all powerful.

@Paperinick Wanda could take the infinity gauntlet since she can remove mouths, and she might be able to just destroy ghost rider into a pile of bones and shrink Galactus but I think Loki could beat her or Thor yeah, oh wait if forgot about deadpool and wolverine, they both can regenerate but we know that wolverine can die cause Logan died but deadpool cant

White Vision maybe might be able to stop Scarlet Witch

Other than that I don’t know if there is anyone else who could stop her