After the failure of Justice League and controversy regarding rewriting and a complete do-over of the film after Zack Snyder left for private matter and Joss Wheldon took the charge.
It gave rise to another version of the movie called Snyder’s Cut which was supposed to be the first part of two movie continuation but with below-average box office performance and shuffling of Warner Bro’s staff.
It seems like the second part of the movie has been kept in a dark shelf with a major focus being given to standalone movies like Wonder woman 1984, The Batman, Aquaman II, FLASH,
but in Hollywood, you can never say never as Wonder Woman director Patty Jenkins showed interest in directing the sequel.
If we follow the Snyder cut storyline it was supposed to follow the story of Apokolips new GOD ruler Darkseid and his threat on Earth with Lex Luthor and Deathstroke playing a significant role, but Jess Wheldon released version changed everything with not much giving away or easter eggs regarding story arc of next movie.
thus it is difficult to guess what will be the next justice league movie based on if it ever takes place in the distant future.
All the major cast member are still under warner bro’s contract like Henry Cavill said he still has one movie left under his contact similarly Jason Mamoa, Gal Gadot, Ezra Miller and Ray Fisher are all supposed to appear for future DCEU movies but
it is highly unlikely Ben Affleck will return as Caped Crusader with mantle being passed on to Robert Pattinson who will star in THE BATMAN to release in 2021
and all the side-cast cast like Amy Adams, Amber Heard, and William Daoef can be hoped to return if the Justice League II is ever being made.