There’s a very simple way to make the Martha scene work. Don’t have Batman be okay with killing beforehand. It would be better if Superman was his ONE exception to his rule. The perceived threat of Superman was so great that Bruce had to change his morals. Then he realizes- https://twitter.com/kryptonscodex/status/1246084660557492224

-how big of a mistake he’s making. How far he’s fallen from what he used to be, stooping down to the same level as the people he fights every night. Then it would work.

This clip shows that Zack gets the point that I’m making here. He’s explaining it in basically the same way I am. The only difference is, Batman has been killing the entire movie and before.