There's a backlog. Unfortunately Darkhold was in it. It really sucks, but I'm not at all shocked. Wanda isn't exactly a priority for Marvel in the books. Which is why I'm happy she's at least that in TV/Movies. Because she'll be somewhere.
But really, Wanda doesn't need any conspiracy theories to why she's not in the books. That was even the case before the latest parental retcon and her being removed as a mutant. She was gone for longer actually.