I really think there should be a follow up story to Dark Nights Metal focusing on the story of the surviving Dark Knights of Barbatos as well as the remnants of his army of dark iterations.
After all, they were essentially dispossessed after their worlds/universes had died.
If their dreams for a place to live were not hijacked by an ancient and malevolent god who wanted to expand his dominion at the expense of the multiverse above, and their methods were not quite as violent, technically you could consider them almost refugees.
One way in which this could be done is you could have the Over Monitor build a kind of permanent structure within or in the outskirts of the Dark Multiverse, a hybrid of museum, tomb, library and refuge.
Call it the Shadow Mausoleum or something.