So now that the Arrowverse, DCEU, and many others are canon in the DC Multiverse, maybe we'll see some hints to this in The Flash movie (which I hope is still happening)
I think the DCEU takes place on the new Earth-1.
I know it's a long shot, but if we get to see the multiverse in the Flash movie, and bc it has Earth-89 Batman, I hope we'll see grant's Flash as well, even for 2 secs, that's enough for me.
In the Crisis post-credits, we see most of the major Earths but not the DCEU Earth, We don't see the New Earth-1 either. So maybe they're the same.