There’s even an allusion to Black Adam early in the film, although not by name.
On why Warner Bros. Pictures had decided to do the crossover later into the franchise, Levi further explained, “Because he’s like the ultimate bad guy for Captain Marvel, Shazam. Like [Shazam and] Black Adam, they’re doppelgängers right, the evil twin to who I am.
“And then it would kind of be, if we do a third Shazam! and a second Black Adam, kind of [parallel] like that, that’s where we would [meet].”
It would just be a movie of us sitting around playing video games for the third one, that would be very boring.