So after reading DM#7, I find myself wondering what this means going forward.
First, the “new timeline” that they were planning appears to have been scrapped, in favor of of a setup where everyone remembers everything. As I interpret it, this is in effect an evolution of the Metaverse from Doomsday Clock: Superman first appeared in 1939, then the timeline was asked in 1957 and several times since then; and after Diana dipped her Lasso of Truth into the Cosmic Forge, everyone in the current iteration of the Metaverse regained memories from all of the prior iterations of the Metaverse.
I'm assuming that this extension of memories only pertains to the primary Earth of the DCU: for instance, Superman didn't gain the memories of President Superman, because President Superman is not and never was from the Metaverse. Spinoff Earths may have acquired a similar unlocking of memories from previous iterations, if “previous iterations” are a thing outside of the Metaverse — which may well be the case, considering Convergence. But it's just as possible that each alternate world is its own thing, with just a single history. Again dipping into Doomsday Clock, you have the archival Earths (Earth 2, Earth 1985, Earth 52, and so on) which were spun off of the Metaverse when its timeline underwent overhauls; and even if Convergence is true and there are new iterations of each, is possible that the “archival Earth” thing happened when those worlds for updated to newer iterations.
That said, I think it would be simpler to restrict the “everyone remembers everything” effect to the focal world of DC Comics.
Second: what's that going to do to people? I have a feeling that therapists are going to be in high demand in the immediate future, as people struggle to come to terms with multiple sets of conflicting memories. And does that mean that secrets potentially revealed and then concealed are now out in the open again? E.g., everyone now remembers that Nightwing is Dick Grayson. Or is that memory somehow immune to the Lasso?
Third, the Two Central Worlds, neither of which is Earth 0. One is called the Elseworld, and is described as the antithesis of the other. Nothing is known about the other. Speculation: the Elseworld is the new reality's version of the Cosmic Forge: it's kind of like the Metaverse in that it's spawning other worlds in the Multiverse; but it's spawning them all the time and in much more radical ways.
As for the other one, it may well be that I'm wrong about Earth-0 being the Metaverse. Instead, Earth-0 may well be merely the latest Earth to be spun off of the Metaverse, with DM's resolution being the triggering event, and the actual Metaverse may be the other central world. The planned “new timeline” may actually still be a thing in this new reality, as the Metaverse's newest iteration. But unlike earlier iterations, it's not the focus of DC Comics.
Or perhaps the other central Earth was previously Earth-33, a.k.a., Earth Prime, a.k.a. us. Which means that it will never be visited by anyone in the comics, except through fourth-wall schticks like what Animal Man did back in the 90s. (The “new” Earth-33, by contrast, would be a reconstituted pre-Crisis Earth Prime, where Superboy Prime found himself at the end of the DM tie-in that he featured in.)
Thoughts?