Honestly, I think these will be less interconnected than people are currently expecting, tbh. Gunn has emphasized that he wants each of these properties to stand on their own, and given how he vocally pushed back against the "interconnectedness" of the MCU in his Guardians films (he was ready to straight-up refuse to include Thor in Vol. 3 if it came to that), I really think he means it. Of course, with corporate studio culture being what it is, they pretty much have to say they're in the same universe, and I'm sure there will be supporting characters that crossover and whatnot. But as far as serving one big narrative, I don't think that's being quite as prioritized here as it was in the MCU, despite that whole "Chaptr One" title. They announced 10 projects (not counting the Elseworlds releases, which will further space these out), and not one of those was anything coming close to a "Justice League" project. I genuinely believe it will be a very slow crawl to get to that point, because Gunn is more interested in establishing each of these characters in their own little corners of the universe in their own stories for now. And for a while at least - certainly longer than the 4 years of build-up the MCU gave us - I expect the "interconnected" nature to be little more than the occasional easter eggs and supporting characters who show up in other things.
Like, for example, I expect Swamp Thing to be totally its own thing, outside of the odd mention of Metropolis or something, and completely different in tone/style to Superman. I do expect the other heroes in Superman to show up in their own projects, of course (which we know at least of couple of them already are), but beyond that? Eh, I'm not expecting constant "Infinity Stone teases" anytime soon, nor am I expecting all these movies to have the same vibe. Making Swamp Thing and The Authority two of your first-announced projects alongside Superman and an especially heavy Supergirl story is basically another way of announcing "we don't want these all to feel the same" imo.
I mean, the obvious route for an interconnected universe would be to start with Superman, Batman and Wonder Woman reboots, and work outward from there. And they are very pointedly NOT doing that. I'd even say they're deliberately avoiding it. Whatever this is, whether it works or not, is certainly a more interesting approach to me.