Hypothetically, if governments wordwide just suddenly became authoritarian and deleted all records of history, you and some survivors escape to a remote area outside of government control, they all can’t remember much from history (either didn’t pay attwntion in class, or suffers memory loss from the governemtn attacks) and so you are designated as this community’s official historian. How much can you remember? What’s gonna be the official narrative of your little rebel community?
I wouldn’t bother with history at that point. History only matters when we can rely on there being a future. And if the big oops happens, all that matters is raw survival and STEM (with the pure M being optional).