As I'm sure any regular editor of this wiki will tell you, DC's continuity and canons are a mess right now. There's a lot to unpack there, but for the sake of simplicity, I want to focus on the omniverse, how there seems to be what I've chosen to call "canon overlap" because of it, and how I think we should document it on the DC Database going forward, because what we have now, quite frankly, isn't working (I'm not calling anyone out, you're all doing great; I just think we maybe need to change our approach to how we separate universes and canons on the wiki).
To set the stage: DC has never had one unified multiverse like Marvel seems to. It's always been kind of in flux what universes are designated where, to the point where we've had I think eight or nine universes designated as "Earth-1" across all DC media. Then along come Scott Snyder's Justice League run and Metal crossover events, and given how fan-servicey and lore-heavy those stories are, I think Snyder recognized this discrepancy and made it abundantly clear that there are multiple multiverses within the wider omniverse. That's a lot of information, but it's enough for me to wrap my head around and make sense of...
...until you realize that certain universes exist in multiple multiverses, sometimes under the same designation, sometimes under a different designation. Hell, multiple universes within the same multiverse can have some identical events. For example, there are four universes for the 90s Batman movies:
In the Arrowverse, (which is a multiverse, not a universe, so that's what I mean when I use that term) Earth-89 is where the first two Tim Burton-directed Batman films took place
Also in the Arrowverse, Earth-97 is the setting for the Joel Schumacher-directed Batman films, no longer canon to the other films they're supposedly sequels to on Earth-89 or in any other reality
ALSO in the Arrowverse, the divergent reality created by the Flash of Post-Crisis Earth-1 has Zod and some of the events of Man of Steel, as well as the aforementioned Burton films
To make things even more confusing, in Multiverse-1 (the comics' multiverse) there exists a world called Earth-789, which is the continuity of not only the Burton Batman films, but also their comic sequels, AND the Richard Donner Superman film series and THEIR comic sequels, even though the Donner films take place on Earth-96 in the Arrowverse as well, though maybe that's just the universe where Superman Returns happened, but Helen Slater's Supergirl is there too, and...
...my head hurts, but I think you get the point, and can see why I call it "canon overlap". Our solution to this so far has been inconsistent and haphazard at best. Obviously, we have pages for all those universes I just listed, but we also have a page for just the "Burtonverse" and the "Donnerverse", which are I guess like catch-all pages? I'm not sure.
So, I think we need to find a new solution. At the very least, we need to have a wider discussion about it, because this just isn't working. I'll start by throwing out my idea: separate pages for each universe, and if characters are entirely identical in multiple universes, no differences at all, merge the character pages, and mark them from being from multiple universes. Kind of like we do for characters whose history on Earth-One wasn't affected when it merged into New Earth during the original Crisis on Infinite Earths.
If anyone else has any other ideas, I'm all ears. I'm just trying to get the ball rolling on a discussion, because at this rate, the wiki is just gonna get more and more and more confusing.