I think too many biopics tried to cover too much of a persons life. I think it's better to just narrow down to a specific period in their life. Or focus on a specific event.

Music biopics should look to a film like Rocketman for inspiration. They not only narrowed down the story. But making it a musical really made u feel what they were feeling at specific moments in their lives.

Then of course have good writing, acting, cinematography, and directing.