That was later debunked, but there’s no reason they couldn’t still be brought in for Suicide Squad 2.
When John Ostrander revitalized the Suicide Squad in the 1980s, one of the first challenges he threw at the characters was a terrorist organization called the Jihad, which was later renamed Onslaught.
One of their later members was a man named Antiphon, and the reason we mention him specifically is because he was rumored to be Suicide Squad’s main villain, with Ed Harris rumored to play him.
In the comics, Onslaught is entirely comprised of superpowered mercenaries.