If production stars in November then a March/April 2021 release date is possible. They need to separate The Batman and The Suicide Squad though. Those two are too close but I suspect is due to the fact that WB doesn't want Batman to compete against Jurassic World on it's 2nd weekend.
I think Flash or New Gods will be early 2021. They are just holding on to the announcement. Probably New Gods for 2022. If they start shooting Flash/New Gods in January 2020 a March/April 2021 release is possible.
They could just skip Deadshot this film and leave the possibility of Deadshot being used in a 3rd film. The beauty of Suicide Squad is that they can rotate line ups. They can have 5 films with a new set of villains to get their heads blown. Personally I wouldn't have brought back Harley Quinn either.