It would appear that the plan now is to introduce Black Adam in his own film, ahead of Shazam (a character who has yet to be cast) being incorporated into the larger narrative tapestry of the DCEU at a later point in time.
The actor has been set to play the antihero/villain Black Adam in a Shazam DCEU solo film for years now, but of late there have been more and more signs that momentum on the project is picking up, ahead of its scheduled 2019 theatrical release date.
Moreover, Kit says that Black Adam himself could first show up (via cameo) in an upcoming DCEU feature like Aquaman, prior to his own solo film release.
Deadline is reporting that Johnson as Black Adam is now getting his own solo movie, as part of the DCEU.