A universe where Marvel went bankrupt in the 1990s and DC bought its characters and combined its superheroes into their own universe.
Just think of all the universes out there: A universe where Ben Affleck made his version of The Batman.
A universe where James Cameron actually directed the Spider-Man movie he spent much of the 1990s developing.
You might see Robert Pattinson’s Bruce Wayne in The Batman months removed from Ben Affleck’s Batfleck and Michael Keaton’s older Dark Knight in The Flash.