My guess, or hot take is that there are two Wanda's, the truly evil Wanda is in fact Lore.
If they are going with the Wanda being a Nexus Being angle (and as they have confirmed that with Kang in Loki, the concept is established), then the "housewife Wanda" in the leaks is a fake, and could in fact be Lore. It's exactly the kind of twist I could see them doing, and if you are going into Multiverses and Nexus Beings, you have to show that concept. There has to be a twist that Strange figures out to show the audience how clever he is, and a compassion and moral conviction (Wanda is a good person) that shows he is, as Ancient One said, "the best of us."
Also, Wanda being tricked by the Darkhold and coming face to face with Lore would be her confronting her worst possoble self, leading to Strange getting through to her and breaking her free of the Darkhold. This fits with the "rediscovery" arc Shakman talked about. Lore is, after all, what Wanda fears she will become.
In WandaVision we get the Mind Stone and Darkhold showing opposing visions of Wanda, then at the end of WandaVision we get the two Wanda's duality again with the astral and corporeal Wanda's.
MCU Lore, let me speculate, is a Wanda who never met Vision or the Avengers. Lore is a Wanda who became bitter and broken, joined Hydra, who unlocked powers, but because she never met Vision and Clint, never found herself again.
The Darkhold, in saying Wanda will destroy the universe, is thus propagating a mischievous half-truth. It fits with the idea of Chthon trying to define Wanda through naming and sly half-truths.
Wanda going psycho-crazy and being mansplained by "white male" Strange, after they made a point of saying they wanted to avoid that sexist stuff, would be utterly bizarre, not to mention that Wanda returning to her Sokovian roots and turning evil, after becoming good whe being in America...that just has a ton of racist undertones.