There is nothing more damaging than taking a character and reducing them to a log line. You can't create ideological differences if everyone is, "on the same page"? Really? Ok - how about I show you the differences in the characters as they exist in the Snyder films.

Superman is a first responder. He shows up when people are in trouble and does what he does to help them and preserve lives. He doesn't seek out trouble, he doesn't pick targets and he doesn't care where he's needed. He finds out people are in need and he goes. He has no agenda.

Batman is a crime fighter. He makes it his duty to stop crimes in progress, investigate crimes that need solving and deliver criminals to justice - otherwise his branding victims wouldn't BE in prison. His agenda is to protect Gotham from criminals.

Wonder Woman is a warrior. She has vowed to protect mankind from otherworldly forces. She makes it her goal to seek out evil and END IT - no bullshit. She's not a cop or a fireman. She's fighting a literal war against darkness and she fights to win.

Three completely separate character types with three completely different sets of goals. "Dark and grim" have fuck all to do with it. If you can't mine, "ideological differences" out of this fertile Earth of storytelling then you simply have no fucking imagination.