The DCEU can set itself apart by doing what the comics have largely done, and breaking down into a collection of smaller universes that each focus on a different DC "family" - like the Bat-family of Batman, Nightwing, Batgirl and other Bat-adjacent characters, or Shazam and the Marvel family, or the expansive world of Aquaman and the Seven Kingdoms. There's still potential for future crossovers, of course, but by dividing the DCEU up, the smaller sub-universes can be allowed to thrive and in a worst-case scenario be quarantined from one another, so that a individual movie can fail without affecting the larger universe.
Warner Bros. has a significant advantage over Marvel Studios/Walt Disney/Paramount at the start of the MCU, in the sense that the DCEU already has the full slate of DC Comics characters collected under one roof. By focusing on individual families - Supergirl and Superman, the Suicide Squad, Harley Quinn and the Birds of Prey - there's huge potential to build up strong brands with their own individual worlds and aesthetics. There's more than one way to build a shared universe.
So all in all, yes DC can have a shared movie universe but of course it can be built towards slowly.
Warner Bros. has a significant advantage over Marvel Studios/Walt Disney/Paramount at the start of the MCU, in the sense that the DCEU already has the full slate of DC Comics characters collected under one roof. By focusing on individual families - Supergirl and Superman, the Suicide Squad, Harley Quinn and the Birds of Prey - there's huge potential to build up strong brands with their own individual worlds and aesthetics. There's more than one way to build a shared universe.
So all in all, yes DC can have a shared movie universe but of course it can be built towards slowly.