“ Backrooms ” is officially A24’s highest-grossing worldwide release, as well as the studio’s first movie to surpass $200 million in ticket sales. The breakout horror hit, directed by YouTuber Kane Parsons, has generated $212 million globally including $135 million in North America. Those returns have surpassed the lifetime haul of Timothee Chalamet’s “Marty Supreme” ($191 million), which previously stood as the indie studio’s biggest movie at the worldwide box office. What’s more impressive is