Rob Roy was a fictional movie based very loosely on the life of the real Rob Roy MacGregor.
The many versions of Macbeth (including the original play) have very little to do with history or the life of the actual Scottish king of that name.
Speaking of Macbeth, Shakespeare in Love certainly fits here, as does George Lucas in Love.
Yes to documentaries/ Then I add Sherman’s March (which doesn’t have a damn thing to do with its titular subject.
Also, how about Howard and Me (the movie about the controversial Howard Hughes will)? Not really a biopic, though Howard Hughes is in the first part of the film. It’s more a character study of the guy who was claiming the Hughes fortune.
Here’s a triple play:
Abbott and Costello Meet the Killer, Boris Karloff (1949)