WHERE DID THE DCEU GO WRONG AND WHAT CAN BE LEARNED FROM IT?
This article has some ideas:
https://www.cbr.com/dceu-not-worth-saving/
What can be learned from the failures of the original DCEU when making a movie DCU?
https://forums.superherohype.com/threads/where-did-the-dceu-go-wrong-and-what-can-be-learned-from-it.559473/