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If we're talking in-universe examples, autobiographies would fall under Her Code Name Was "Mary Sue".
See also Poe's Law and The Tyson Zone when they're so off the deep end that its hard to tell what is and isn't made up.
Nero is an example from the ancient world: he probably didn't have part of Rome burned, but he did build his new palace in the cleared land via ambiguously legal real estate deals and fund it with public money. He probably didn't kill people who refused to show up, but he did apparently put on extremely long Giftedly Bad one man shows that you were obligated to show up to and praise if you wanted to curry favor.

Is there a trope for a biography that seems hard to believe mainly because it casts the person in an incredibly negative light (or, conversely, seems to whitewash them a lot), as well as the claims in it being rather far fetched and/or contradicting what other people who knew the person in life claimed about them? I only have a Real Life example so I would prefer not to say it due to Rule of Cautious Editing Judgment.