Only way that can work for my school of playing is that if in the Storyteller’s section there would’ve been “Storyteller, before your group does anything else, you need to decide the canon truth about these things:” followed by a checklist where you could literally check, circle, or write in the actual truths. (Like Starforged and Burning Empires both do.)
And “meta plots” where stuff is gradually revealed module by module are right out.
That said, maybe this sort of truth-fuzziness is more OK for stuff that’s ancient history compared to stuff that’s more directly relevant? Although in my game world I have secretly decided on the true nature of the gods, the elements, the timelines, the old ones, and the planes.