I don't know if it's harder but when you're playing a real person you want to honor their memory - even if they're a criminal or someone that the public loathed. That can be challenging.
“Narrative becomes the way you make sense of chaos. That's how you focus the world. It's the only reason you should ever try this writing job.”
“My mother thought Hollywood was a den of iniquity, and people came to terrible bad ends there.”