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

You're not going to Kill her unless you sneak up on her as she's a glass cannon with extremely weak defense. You have to stop her and get her back on the good side like what America and Strange did in DSMOM or else you're going to be in the next episode of Wandavison sitcom world or your just plain dead lol.

Even before she become the Scarlet witch, she was the closest to defeating Fully Powered Thanos and she was destroying a Freaking Infinity Stone at the same time. Imagine if she was only focusing on Thanos what would happen instead of trying to kill her loverboy.

Maybe infinity ultron, supreme strange or the spot lol @IronWidowMaikuB

Infinity Ultron maybe but even them Wanda could just destroyed the Infinity Stones again and he's back to just Normal VisionUltron.

The Spot Just No lol. Wanda would cook Spot so fast.

Supreme Strange might have a chance but only if he sneaks onto her.

lol only one above all then for sure

Red grape melon playground, it's too harf Wanda take the infinity gauntlet when Thanos protekt it using the infinity stones. Also Wanda can't shrink Galactus, Galactus is bigger than a galaxty and she hash't this ability.