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 literally have multiple copies of Wikipedia offline. Including one on a USB stick.
I don’t think it would ever be possible to delete all records of history short of blowing up the entire planet at which point its quite moot.