Does DCEU not have a Vision head in the same manner MCU has Fiege?
The decision was made to let directors make the film they envisioned after the last big reshuffling of executives at the top of WB studios.
So instead of their movies being managed by one guy's vision for what he wants like the MCU does with Fiege; over at WB the DC movies are more director focused films and the idea of an "Extended Universe" is basically there if the folks making the movie want to utilize it but it's not something that is being forced on them while they are making their movies.
This is basically what's going on with DC movie:
1. Some films occur in their own universe (Joker)
2. Some films occur in the shared universe where the heroes exist and interact with/reference one another (Birds of Prey/Shazam)
3. Some occur in that shared universe but only focus on the character the movie is about (Aquaman/WW84).
This Suicide Squad film is an instance of #2.