Why does Stephen Strange seek out the Scarlet Witch's help in Wanda Maximoff into the MCU's Scarlet Witch, a being whose creation was foretold by the Darkhold and who apparently wields more raw power than even the Sorcerer Supreme. According to Agatha Harkness, she is destined to destroy the world itself - making her a potentially unwise ally for Doctor Strange.
And yet, presumably considering Wanda Maximoff an ally after the events of Wanda's power-up as the Scarlet Witch, and why he thinks she can help him.
Doctor Strange and the Masters of the Mystic Arts didn't interfere during the events at Westview, but the Doctor Strange 2 trailer nonetheless confirms they know about it. When Scarlet Witch says she expected a visit, Strange reassures her he hasn't come in response to what happened at Westview. The sorcerers must have learned of Westview after the fact, and subsequently looked into it; they'd certainly recognize that Wanda had become an incredibly powerful sorceress, although it's difficult to say whether they'd have been able to identify Chaos Magic. In the comics, Chaos Magic is tied to the sinister Elder God Chthon, and he ensured sorcerers believed it was just a myth so they wouldn't be prepared for his return to this plane of existence. It's also entirely possible that they were more understanding of what happened given Wanda's intense grief at the time.
Still, Doctor Strange would no doubt be fascinated by the fact Scarlet Witch has learned to tap into such powerful magic without training at Kamar-Taj. It's important to that, in the MCU, magic is itself tied to the multiverse. As the Ancient One explained in Doctor Strange reading the Darkhold, the book of dark magic Wanda took from Agatha Harkness.
It is, however, possible Doctor Strange knows even more than this. The Masters of the Mystic Arts don't possess the Darkhold, but they do have a considerable library of books of magic, and some of these may mention the Scarlet Witch. If they do, they may make clear she has powers beyond even the Sorcerer Supreme, even the ability to travel the multiverse at will. That kind of knowledge would certainly explain why Wanda is sought out in Doctor Strange in the Multiverse of Madness - even if the Masters of the Mystic Arts don't know the entirety of the dark prophecy surrounding her.
