Fan Casting Batman/Bruce Wayne in Justice League Apokolips: Chapter 3

Perhaps Bruce has brought two samples of the Lazarus pit from his time trip to Gotham and synthesizes a virus that will rend Darkseid temporarily comatose. Has help from Highfather who helps him study Darkseid's physiology? Similar to the infinite crisis where he shoots Darkseid with a gun however in my story he would inject him with it? Maybe Superman does it whilst Batman and the rest of the League wear him down?