We've already had the first WW movie, set in 1917. Now, in the next few years, we're getting-
-Wonder Woman '84, set in 1984.
-Joker, rumored to be set in the 1980's.
-Supergirl, rumored to be set in the 1970's.
Add to that the fact that Matt Reeves' Batman film is supposedly set in Batman's early years and might not be set in the present-day as a result.
It does make me wonder if this is the way forward for DC. Doing away with the shared universe and setting their films in the past, during the heyday of superhero comic-books.
Fox's X-men films of course are what set the ball rolling on period pieces, but the MCU has also done a fair bit as well. Maybe its now DC's turn.