Elizabeth Olsen explained in the interview with Marvel that
Earth-838 Wanda's powers appear to have been awakened after she was possessed by Earth-616 Wanda, and this could lead her down the path to realizing her potential as the true ruler or destroyer of the multiverse.
Wanda 616, our Wanda, is much more powerful than Wanda 838. At the end of WandaVision, we see our Wanda become the Scarlet Witch, which means she has even more power, energy and potential.
After her Earth-838 self tells her “Know that they'll be loved,” the Scarlet Witch says that no one will use the power of the Darkhold again. Making good on her word, she uses her chaos magic to collapse Mt. Wundagore - destroying all copies of the Darkhold across the multiverse and burying herself within Mt.
Elizabeth Olsen explained in the interview with Marvel that Wanda from Earth-616 was leagues stronger than the Earth-838 version but was held back because she was still tethered to her physical body, so it took a great toll on her to fully control a character from another universe.
Earth-838 Wanda's powers appear to have been awakened after she was possessed by Earth-616 Wanda, and this could lead her down the path to realizing her potential as the true ruler or destroyer of the multiverse.
Wanda Maximoff has never truly been defeated, only "losing" to the combined forces of Doctor Strange, Wong, and America Chavez after realizing the error in her ways. For a time, Wanda posed the greatest threat to the Multiverse, going on a violent rampage on Earth-838.
Thor's immense strength, combat prowess, control over lightning, and enchanted hammer, Mjolnir, make him a formidable opponent against Scarlet Witch. In Avengers: Age of Ultron, he demonstrated his ability to resist her reality-warping powers and even physically overpower her.
Back when Wanda Maximoff was considered a mutant, she was never given a classification. However, after she was retconned to not be one, X-Man created the Age of X-Man where everyone is a mutant and Wanda is referenced as an Omega mutant.
In the Marvel Cinematic Universe
In WandaVision, however, Wanda is revealed to be a powerful sorceress, the only being currently capable of wielding chaos magic. The series explores her ability to manipulate reality like her comic counterpart.
Wanda Maximoff lived with her sons, Billy Maximoff and Tommy Maximoff when her body was possessed via dreamwalking through the Darkhold by her Earth-199999 counterpart; who used it to infiltrate the Illuminati and kill all of their members. After Wanda's body was released she returned home.
Earth-838 Wanda is alive after the events of the movie, and if she returned, it gives us another in to bring Billy and Tommy into the Young Avengers. The Illuminati are dead in this reality, but remember that Baron Mordo (Chiwetel Ejiofor) escaped the massacre.
John Krasinski's Reed Richards is Earth-838 Wanda's Husband, Real Father of Billy and Tommy – Theory Explained.
In the main MCU timeline, Scarlet Witch doesn't physically give birth to her kids, but she does create them as part of the illusion about what her and Vision's lives could have been.
The variant of Wanda in the 838 universe actually really lives in WestView with her two real children.
In short, Wanda may be the most powerful, but Doctor Strange is more skilled and strategist. Even so, he would hardly be able to defeat his fellow sorceress by himself (something the new film makes very clear).
However, Black Bolt would likely have annihilated Wanda with a single word. It's evident that the Darkhold-corrupted Scarlet Witch is incredibly powerful as a prophesied wielder of chaos magic.
If it came down to it and Odin saw Scarlett Witch as a threat to the Universe and Multiverse and decided to try and take her down, who would win? Odin. Odin could probably kill her but not in a strait up fight.
Scarlet Witch has proven to be more than a match for many foes, but she's not unbeatable. More than a few DC characters would defeat her with ease. Scarlet Witch has had a long career in the superpowered community.
Scarlet witch's biggest weakness is her durability. The only mode of defence was her powers. So her durability depended on her powers. She had two different stages in her power: before Infinity war and after Endgame.
Scarlet Witch's most important aspect in this fight is that she has the ability to defeat Superman. He is not impervious to magic, so her hits will damage him.
Another major difference is the lack of Avengers in Earth-838, even though they still have Dr. Stephen Strange and a Captain Marvel.
Elizabeth Olsen too played different versions of her character Wanda/Scarlet Witch. The major role in the movie was of the Scarlet Witch of our universe Earth-616 and of the variant on Earth-838.
While Captain Marvel received her powers after being exposed to an Infinity Stone, WandaVision reveals that Wanda's exposure to the Mind Stone amplified powers she was unaware she had already possessed.