Maybe this will help.
After his odyssey through the DC Multiverse, Wally West may find his ultimate redemption as the heroes' last great hope in the current crossover event Dark Nights: Death Metal.
Writer Scott Snyder confirmed Wally's brief confrontation with the Batman Who Laughs in the epilogue to Flash Forward will be expanded on as the crossover continues to unfold. Snyder hinted Wally will continue to boost his newfound powers through raw Crisis energy on his trip into the Dark Multiverse, from which the Batman Who Laughs invaded the DC Universe.
"The idea is Wally's body has been prepared, in a way, by having this [Doctor] Manhattan energy to be powered by all this Crisis energy," Snyder explained in an interview with CBR. "And the hope is that he can rival the Batman Who Laughs and even Perpetua if they can fuel him with the energy from the Dark Multiverse from these worlds where the Crises are still happening. The goal is to power him up so he can fight the Batman Who Laughs once and for all but, of course, there's twists and turns and things happen that make that confrontation different than you'd expect when it actually happens."
https://www.cbr.com/flash-wally-west...metal-endgame/