Ryan Coogler's grandfather inspired his ambitious new vampire movie 'Sinners'

TheStewartofNY/FilmMagic; Warner Bros.; BI Ryan Coogler has dazzled audiences with big-budget Marvel movies (the "Black Panther" franchise), introduced a new generation to the Rocky Balboa saga ( "Creed," "Creed II"), and painted a devastatingly human portrait of a real-life tragedy ("Fruitvale…