All this could be explored in Doomsday or even in a Scarlet Witch movie. Like there's a lot of story you can do with Wanda. Each stories of her has potential to become a very good story. It's infuriating how Marvel has not released or greenlit a Scarlet Witch movie yet but has th0r 5 in the works. Like make it make sense!

At this point, I don't care how they bring Elizabeth Olsen as Wanda back. Just make her return please. I cannot fathom how their most popular female character and very well written (until MoM. With Waldron. Sigh), is absent from this MAJOR film. Her destiny to rule or annihilate everything is such a delicious concept to explore, whether that can be villainized or the key to saving the multiverse against Doom.

I think the reason why Wanda is not in Doomsday is because she will be the central most important part in Avengers Secret Wars.

Here's my theory:

What if Loki is destined to step down from the throne in the Tree of Yggdrasil because that chair isn't really meant for him hence Dr. Doom will take him down and take his place (Doomsday)

Because someone is literally written, destined to rule the cosmos, the Scarlet Witch?

She's literally written in the darkhold with an illustration of herself and the multiverse in the background AND a statue at that! 

Since Wanda failed to annihilate the multiverse in MoM?

in Multiverse of Madness, Wong said "The Scarlet Witch is prophesized to RULE OR ANNIHILATE THE COSMOS"

It's basically 2 choices. Since annihilation of the cosmos did not happen, Wanda will RULE the cosmos which will formerly be held by Doom, and Wanda defeats him, taking his place, and fulfilling her destiny of ruling everything at the same time redeeming herself!

Hitting 2 birds with 1 stone!! Redemption and Darkhold prophecy fulfillment! 

Also, her statue in Multiverse of Madness and the Scarlet Witch illustration from the darkhold has circles around her which symbolizes the multiverses and the HEXagonal shape around them is a representation of Wanda's hex keeping them intact. And the Scarlet Witch figure is in the middle of all that, meaning she's like the "anchor" to these multiverses. 

And that Scarlet Witch costume in the statue is not the one from Wandavision and Multiverse of Madness! It could be a foreshadowing of what's to come! 

If you compare the Scarlet Witch statue costume to Loki's new costume, you'll see how the fabric and how they're woven is very similar! This could signify Wanda ascending into an even more powerful version of herself with a new costume exactly as the statue, as she holds the multiverse after she defeats Doom.

No please. As much as I love Lizzie, as a hardcore MCU Wanda stan, I need her to save everyone in Avengers Doomsday and Secret Wars first, then a Scarlet Witch movie, even a trilogy, I need a woman led trilogy Marvel movie about witchcraft and the darkside of the MCU, the Scarlet Witch solving different supernatural anomalies, maybe spirits of previous Avengers who have died that she will interact with as either guide or a newfound foe. And then more appearances and then this old version. I need to see how she fulfills the darkhold prophecy and to see that costume in the statue worn by Lizzie, because that has not been fulfilled yet! And what are the circles behind the statue mean, and why is it enclosed in a hexagonal shape with her in the center?

Elizabeth Olsen's Scarlet Witch is the only reason is I am staying in the MCU, and she's recently the MCU's popular character AND very well developed one at that (even though Multiverse of Madness feels rushed for her villainous turn) so I believe she will be back most probably in Doomsday and Secret Wars. Her name better ring a bell for powerful villains like Doom to manipulate her for their bidding, but I think that's how the film happens, Wanda will realize she is being manipulated again and will not allow it anymore and will face Doom himself, because frankly, Wanda is the only character having the power to face this kind of villain currently, unless they pull the Antman 3 stunt on Doom. This is where Wanda's redemption starts, protecting her old allies and newfound friends to this HUGE threat!