Soto is 26, as noted above, and hasn't just played for three teams already - he has made the postseason with all of them. He was already the youngest player to reach the postseason with a third team. Now, he will aim to do so with a fourth team. Only one player has appeared in a postseason game for a fourth team before the age of 30: 29-year-old Delmon Young for the Orioles in 2014. Soto will get three chances to shatter that record.
He hasn't just made the postseason with those three teams, he's homered for each in the playoffs as well. The record for most different teams to hit a postseason home run for is four, held by Russell Martin, J.D. Martinez, Mike Napoli, Nelson Cruz, John Olerud, Reggie Sanders and Ron Gant. Of course, this is Juan Soto, so he doesn't just have one home run for each team, he has at least two. He is one of nine players with multiple postseason home runs with three different teams. Nobody has done so for four teams yet.