This is a secret sequel to Glass
I am surprised nobody has guessed this happens in the same universe of the Glass trilogy. All the clues:
-The government sends a whole army to arrest the Butcher, but they don't try to kill him, just capture him like they do with David Dunn and the Horde in Glass.
-Copper has an incredible force, aside of intelligence, and IS capable of throw a Swat for the air after being teased, as the Beast in Split.
- The old woman if the FBI, presented in a distant and mysterious way, could be another member of the Clover Cabal whose mission IS to capture metahumans, as Dra. Staple in Glass.
-Cooper had a traumatic relationship with his mother, as Kevin in Split. Also It appears to follow the same thesis of psychopathology as a superpower.
- Cooper has a sidekick Who loves him, his daughter, as David had his son, Elijah had his mother and Kevin had Casey.
- The film has an open ending and a scene after credits, as Split.
Let's see which is Shyamalan Next project...