Well, it certainly wasn't "Agatha All Along" all along. The series was first announced as "Agatha: House of Harkness" but was renamed in July 2022 to "Agatha: Coven of Chaos". Just over a year later it was "Agatha: Darkhold Diaries" and, at one point, "Agatha: The Lying Witch with Great Wardrobe" (although that last one may have been a gag). Marvel put the name changes down to witchcraft.