But for the sake of argument, let’s ignore Diana stopping those criminals at the beginning of Wonder Woman 1984, and only focus on her main mission in the movie, i.e. stopping Maxwell Lord and Barbara Minerva. As the story progresses, Diana learns that the wishes granted by the Dreamstone come at a cost. For her, wishing Steve Trevor back to life resulted in her power slowly diminishing. In order to be at peak strength, Diana must either revoke her wish, i.e. send Steve back to the afterlife, or destroy the Dreamstone, which, by that point, Maxwell Lord has become.