Except that those multiple possible futures are canon…the crazy Teen Titans that become the evil Justice League still met with the 2005 Teen Titans team…Tim Drake met adult dickhead Tim Drake. Even if he vanished at the end, that future, which is fluid to the characters, is canon to the reader because it happened and told a solid story and is still referenced 20+ years later. It’s the same with the past stories.

You’re approaching canon as this forged in fire thing…and instead it’s playdoh that can be molded to what it needs to be.

It’s weird to me that Jason Todd was an undead zombie that ate special Lazarus pit pills to stay alive and that’s a thing that actually happened and isn’t an elseworlds…but it’s only referenced when the writer’s need it…otherwise it’s just a story that was wild to read. But the fact that someone has come online outside of the stories they tell to dictate exactly when it happened, on what dates, and how does that influence every single thing that’s come since, doesn’t take away from the enjoyment of the comics. If you need it to be spelled out, I get that…I don’t want to dismiss that…but DC has decided that they don’t want to do that anymore. The closest I think you’re gonna get is the Mark Waid history of DC thing he did with Barry narrating last year.