Taking out all the background fluff on Cyborg, Aquaman, and Flash and making them into some sort of short film would help. You don’t do your big team up film and spend a significant chunk of it on mini-origin films for half your cast.

Correct the aspect ration. The film is essentially part of trilogy within the DCEU of Man of Steel and Batman V Superman and is incredibly jarring to watch after them due to the tacky aspect ratio. It’s like he was making a nod to Whedon’s weird aspect ratio for Avengers: Assemble that doesn’t match Avengers: Age of Ultron.

Fix the terrible colourgrading of all three films in the trilogy.

I’ve not seen the other cut since it released but you could probably take all the scenes that don’t cause continuity errors, add them to this cut (once the terrible colours and framing have been fixed) to replace the endless flashback stuff and split the film in two.