After his sudden death at 54 in 2016, Prince’s musical legacy was never a question. But as details emerged about the fentanyl overdose that killed him, stories about his staunchly protected private life began to paint a more complicated picture. Over a 9-hour documentary, director Ezra Edelman seeks to lift the veil on Prince in a nuanced manner, writes New York Times Magazine deputy editor Sasha Weiss. She’s one of the few people who have seen the film after spending a year and a half covering Edelman’s progress—and a dispute with Prince’s estate and Netflix may keep it that way. The deeply p…