Don’t swing sounds like the worst advice to give a hitter. After all, the only way to win a baseball game is to score runs, and the only way to score runs is to put the ball in play (you can’t count on walks that much), and the only way to put balls in play is to swing. Duh.
Over at The Athletic, however, Eno Sarris wrote a big long treatise that basically comes down to this quote: “With the current rules of the game, hitters are more productive when they swing less often.