In the mix of downloadable wallpapers released for the DC FanDome event, some art for Zack Snyder's cut of Justice League was released with what might wind up being the official title.
When it was announced back in May that Snyder's cut of the film was headed to HBO Max in 2021, it was accompanied by art using the title "Zack Snyder's Justice League."

As you can see here, this particular poster for the cut has a different name...