We've said it before and we'll say it again. We're certain that the Scarlet Witch did not die in Doctor Strange in the Multiverse of Madness. Not only is Wanda powerful enough to survive a mountain crashing on her, but she's also Earth 616's resident nexus being (well, in the comics anyway).
There can only be one nexus being per universe, so that gives Wanda extra powers in terms of altering reality as we know it.
Wanda's status as a nexus being means she possesses the ability to alter probable outcomes in her favor (like the Stark bomb never going off!). She may have destroyed all of the Darkholds across the multiverse, intending to sacrifice herself in the process, but if the Scarlet Witch had even the smallest desire to live, the odds are definitely in her favor.
There's simply far too much story left to tell with the Scarlet Witch to end at Wundagore Mountain. We'll see her again. The question is, when?