I doubt they'll have a bunch of books running ongoing with the same IP actively competing against one another at all times.
I'm expecting there to be books where we can catch a glimpse into 1G and 2G (those are the ones Didio said stories were coming for), but I'd be surprised if it were more than a mini or aspects of a book not directly about just that.
Like, in Snyder's JSA I'm expecting to function as almost a 1G anthology book with the JSA at its core. I have to imagine 5G will be the focus of the line, or at least the very tip of the spear, but there's gonna be less comprehensive gateways into Gs 1 and 2 in some form or another along with us likely not being completely without Bruce, Clark, and Di in the present in an effort to make this feel like a continuation of something as well as a starting point for new people.