There are a lot of great locations in the DC Universe from the Batcave to the Hall of Justice, but we have yet to get our eyes on Superman's fortress of Solitude in the DCEU. As it turns out, we already have, but it's not the Fortress we've had in mind.
During his live commentary on Batman v Superman: Dawn of Justice, director Zack Snyder explains that the Fortress of Solitude for Henry Cavill's Superman is more of an internal place rather than a physical place. It's actually alluded to in the scene where Superman is talking to Jonathan Kent:
If anything, there are some similar elements to the actual Fortress from the comics. For one, it's a snow-covered place where Superman can be alone; and what's more, he gets to have a conversation with his father; but rather than Jor-El, we have Pa Kent offering his wisdom.
It was said that the original concept for the Fortress was the Kryptonian ship from Man of Steel, but seeing as how the government took over that, Superman will probably have to look for some other headquarters. If anything, Snyder could retcon his idea somewhere down the line. In Man of Steel, Superman's weakness was the Kryptonian atmosphere, but in Batma n v Superman, it was retconned to be actual Kryptonite.
Everyone is still hoping for WB to release the Snyder Cut version of Justice League, but WB probably has bigger fish to fry, what with COVID-19 effectively closing everything. Heck, even The Flash was supposed to start shooting in April before the lockdowns started taking place.
For now, the next DCEU film, Wonder Woman 1984, is set to come out on Aug. 14.