https://screenrant.com/snyder-justice-league-deathstroke-future-joe-manganiello/
Manganiello spoke to the Happy Sad Confused podcast about the character and implied there could potentially be a future for Deathstroke. The actor revealed his character was set to appear in the Suicide Squad sequel at one point, but those plans were ultimately nixed. So, too, were plans for the Justice League sequel he would've appeared in.
Still, Manganiello predicts a lot of excitement for the future of his character after viewers see what Snyder has done with Deathstroke in the Justice League Snyder Cut:
I think there's going to be excitement over continuing what Zack was up to.