DC Studios co-CEO James Gunn clarifies what The Flash resetting the DC Universe means and how it impacts which actors stay. The official announcement for Chapter 1 of the DCU came this week after Gunn and Peter Safran spent months mapping out their overall vision. The DCU slate included 10 new movies and TV shows that will all be connected in a single universe. However, the co-CEOs also addressed the 2023 DC movies that are already coming and how they connect to the new shared universe plans. This included Gunn confirming that The Flash resets the DC Universe.
https://screenrant.com/the-flash-movie-reset-dc-universe-james-gunn/