The Suicide Squad and Black Adam could be the first two steps toward a brand new DCEU. As a part of the post-Justice League DCEU, The Suicide Squad is simultaneously James Gunn's reinterpretation of David Ayer's Suicide Squad and a spiritual sequel to the 2016 movie. It will take the best elements from the original, like Margot Robbie's Harley Quinn and Viola Davis' Amanda Waller, and incorporate them in a film that thankfully isn't riddled with corporate meddling. Black Adam also has its roots in the original plans for the DCEU, but it will introduce Dwayne Johnson's antihero as a more prominent figure than originally planned, due to the absence of key characters like Ben Affleck's Batman and possibly Henry Cavill's Superman.
In the comics, Black Adam joined forces with the Suicide Squad to battle the sorceress Circe during the "War of the Gods" comic crossover event. Black Adam's anti-hero nature helped him fit perfectly in the team. However, since the Egyptian powerhouse tends to have bigger objectives than those of Amanda Waller and her group, his godly abilities and fiery temperament put the Squad at risk and prevented him from being a full-time member. Nevertheless, Black Adam is open to join forces with them if their goals align.
When Gavin O'Connor was attached to direct the Suicide Squad sequel, Dwayne Johnson's Black Adam was set to appear in an antagonist role. After the original script went through numerous changes, The Suicide Squad transformed into a soft-reboot with a heavy comedic tone, while Black Adam was confirmed to have his own solo movie sometime in the future. But with enough time, the surviving members of the Suicide Squad could forge an alliance with Black Adam to either save the world or fight a common threat. This coalition could arrive as early as Shazam 3, where Task Force X could help Black Adam balance the fight against Billy Batson (Asher Angel/Zachary Levi) and take down the whole Shazam Family.
The villainous team-up would help fix the DCEU's tone and continuity. Harley Quinn has a history with Ben Affleck's Batman and Black Adam is destined to face off against the titular champion - as it was set up in Shazam!, where the Justice League was clearly an established team. By uniting forces, Black Adam and the Suicide Squad could reconcile all the drastic changes the DCEU has gone through and streamline all the movies after The Flash's multiversal adventure while acknowledging the events of previous movies like Justice League and Batman v Superman: Dawn of Justice.
It's safe to say Dwayne Johnson will bring his idiosyncratic balance of comedy and drama to Black Adam, making it similar to James Gunn's characteristic style in The Suicide Squad. These villains don't cross paths as often as other major antagonistic DC figures, but they could establish a solid continuity that drifts apart from Zack Snyder's mature style in the next installments of the DCEU and give the franchise a fresh start without rebooting it altogether.
