Adam B. Vary Senior Entertainment Writer SPOILER ALERT: This story discusses major plot points, including the ending, of “Ant-Man and the Wasp: Quantumania,” currently playing in theaters. One day in early 2020, Jeff Loveness got a call from his agent telling him to go to the Marvel Studios offices in Burbank by 3 p.m. that day, with no further information. It wasn’t until he walked into the meeting room and saw director Peyton Reed — who’d helmed Marvel’s “Ant-Man” and “Ant-Man and the Wasp” — that Loveness understood that he was there to talk about a third movie starring Paul Rudd’s incredible shrinking superhero. But then Loveness was asked a surprising question: “Do you have a take on Kang the Conqueror?”