According to THR, The Shallows and Orphan director Jaume Collet-Serra is the top pick to direct Black Adam. The DC Comics character started out as Shazam's top villain, with a mythology also linked to the same magical energies. The difference is Black Adam's character is far more ruthless, however in recent years he's become something of an antihero. That's just kind of how things work in comics. Become popular enough and writers will soften you up.
Collet-Serra may not be the most inspiring choice of directors but he fits into the WB pattern of filmmakers who have experience in the action and horror genres. He also just finished working with Johnson on Disney's Jungle Cruise, so perhaps the actor put in a good word.
Assuming the production kicks off next year as expected, we could see Black Adam in theaters in 2021.