Today, we can’t stop watching Tom Pelphry on the Netflix series “Ozark.” He plays Wendy Byrd’s wayward brother Ben, who is grappling with bipolar disorder amid the tensions of the drug cartel’s dealings. Pelphry discusses how he prepared for his intense breakout role in Season 3, about playing scenes opposite Laura Linney and Janet McTeer, and how working in soap operas shaped him as an actor.