Some say the simplest thing for the 76ers to do is acquire a third star. The best way for the Sixers to win an NBA title is to pair a Bradley Beal- or Donovan Mitchell-type player with Joel Embiid and James Harden. So they say. But the Sixers need to find the right fit for their All-Star duo, not the best available player. And they must find a way to utilize that player’s strengths. If not, they’ll continue the cycle of turning standout acquisitions into high-priced role players who become vilified in Philadelphia for not living up to outside expectations. Al Horford and Tobias Harris, and to …