The DC Universe’s Elseworlds banner is intended to be used as a way to release movies and shows without requiring them to be tied to the main timeline and universe of the DCU itself. This opens up a host of possibilities for the franchise and ensuring successful series like The Batman can continue in their own cinematic corner.
While it’s unlikely the original plans for Justice League 2 would be greenlit for Elseworlds exactly the same as they were imagined, releases like Justice League: The Flashpoint Paradox movie show that DC isn’t afraid to verge close to the kind of plotlines the movie would entail. As such, it still isn’t impossible that the release could emerge in some transformed shape further down the line.
Similarly, while Snyder has discussed moving away from the superhero genre, he’s also discussed being willing to work with DC again in the future, meaning that a slim chance does still remain.