Why all 3 teams do this:

Spurs: They get a 2 time all-star in Zach, who is a borderline elite 3 level iso and off-ball scorer when healthy. He shot just below 46% on C&S 3s in 2022-23, while taking 3 C&S 3's/game, and half of those were off screens w/o the ball and handoffs. The Spurs have enough cap space to take on his contract, he has only 2 guaranteed years left(the final year is a PO, assuming he's healthy and balls out, has a decent chance of declining). Add that when Pop coached Lavine in the Olympics, we saw Zach buy into a off-ball scoring and defensive role. Also they get the protected PDX first.

Bulls: They go full rebuild mode, trading away a star that's "not seeing eye to eye" with the Bulls FO. They get KJ who is a perfect fit alongside Coby and Ayo(I don't see Josh Giddey having a future here in Chicago). Keldon is a solid scorer, shooter and defender who can start or play off the bench. They get WCJ back, he can stretch the floor, protect the rim, and switch onto guards in screening actions pretty well. Plus he's on a cheap deal. Add Zach Collins for salary + our top 10 protected pick that was held by SA back and a 2026 second.

Magic: They get Vucevic back, and they can/use him like the Kings do Sabonis to offset the fact that they don't have a starting caliber PG. They can use his passing out of DHO and mid-post scoring. And his ability to space the floor allows more driving lanes for Paolo and Franz, also WCJ didn't fit as well with this team as Vucevic does currently.