That kind of story is not uncommon.
All the King's Men by Robert Penn Warren is a novel about a fictional politician running for Governor in the state of Louisiana in the early 1930's. The central character is Willie Stark. Given the time and the place that the story takes place, you can look up the real characters and see that Willie Stark took the place of the real Huey P. Long.
Huey Long was a controversial figure in Louisiana politics. His actions influenced things there into the 1960's - despite his having been shot and killed (assasinated) in 1935.
The story of Willie Stark takes some of the events from Huey Long's life and uses them to provide a background for things that the author has to say about people and politics. Rather than try to put words into real peoples mouths, the author created his own cast of characters so that he could make them say and do what he wanted - and draw his own conclusions from them.
Note, though, that the author had more in mind than just telling the life story of Huey Long. All the King's Men isn't a biography of Huey Long. All the King's Men is a story about the motiviations politicians and people, and it used Huey Long's life as a scaffold.
I rather enjoy stories of that kind.
Real life writes interesting stories with twists that would be difficult for an author to come up with and make believable. Writing a story based on real events gives the story a reality that pure fiction has a hard time matching.
At the same time, changing the characters allows the author to make a more interesting story. If you write a biography, then you have to stick to the facts. If you write fiction based on reality, then you can make the hero more likeable (or less.) You can make the hero see and correct an error that the original made - or provide an alternative explanation for why things went wrong.
David Drake does that in many of his novels. The action (military science fiction) takes place in a far future with interstellar traffic and ray-guns - but the plots are all taken from real events in ancient history. People are people, regardless of how advanced the technology may be. His stories have a "ring of truth" that I miss in many stories written by people who just sit down and make stuff up.
All the King's Men popped into mind because I saw the Sean Penn movie from the novel a few weeks ago on TV.
It was rather surreal to watch Louisiana politics from the 1930's playing out in German. Though I am an American (from Louisiana,) I live in Germany. Imported TV shows and movies are almost all dubbed in German on TV here.