There are still a ton of questions surrounding The Flash movie. Will it be released? What will happen to lead actor Ezra Miller, who could be facing criminal charges? How will it change the DC Extended Universe amid this array of restructuring? Needless to say, there are a bunch of issues and problems to solve regarding just this first solo movie, but that hasn't seemed to have stopped DC from preparing a sequel.
As stated in a report from The Hollywood Reporter, it's noted that there is already a script for a sequel to The Flash, and that it was penned by the writer behind Aquaman, David Leslie Johnson-McGoldrick.
It's said that the script has been prepared in case the movie "does well" when it debuts on June 23, 2023. However, this is surely dependent on the proceedings revolving around Miller as well. Either way, hopefully it won't be too long until we know what the future holds for The Flash.