In Zack Snyder's Justice League 2 script, the Justice League would lose badly to Darkseid.
Superman would become a slave to the villain in his castle, Darkseid would invade Earth and Aquaman, Ajax, and Hal Jordan would die.
Then Wonder Woman, Batman, Flash and Cyborg join the Suicide Squad to defeat Darkseid, but lose again, this time with the deaths of several.
Wonder Woman would die trying to defend Lois Lane from Darkseid and more, but Warners canceled it for being too dark, and indeed, Zack Snyder said it would be a horror movie.
Thanks for reading: What Zack Snyder movie did Warner Bros cancel?, Sorry, my English is bad:)