The third (and last?) season of “ Euphoria ,” HBO’s crushingly bleak portrait of wayward youths in Southern California, sees its coterie of high school friends navigate the seventh circle of hell — which, in the eyes of its creator, Sam Levinson , means entering the world of sex work . Rue ( Zendaya ) goes “Maria Full of Grace,” smuggling fentanyl from Mexico to America in her body and working as an assistant manager at a seedy strip club to work off her substantial debt to Laurie; Jules ( Hunter Schafer ) is raking in big bucks as a high-end sugar baby to a plastic surgeon who enjoys mummifying her in Saran wrap; Cassie ( Sydney Sweeney ) starts an OnlyFans to pay for the $50,000 in wedding flowers she apparently needs to marry Nate ( Jacob Elordi ); and Maddy ( Alexa Demie ) reluctantly becomes her ex-friend Cassie’s manager, intent on transforming her into the next Sophie Rain .…