Just as a side note, not sure which team would want the draft capital in this deal so I didn't include any.

Bulls:

The Bulls are simply destined to win 35 games under Billy Donovan for the rest of eternity, so let's at least help them make more sense as a basketball team. As presently constructed, Chicago is an extremely flawed half-court defense, as Vucevic simply can't hack it on that end right now athletically. If it weren't for Matas' weakside help and Billy Donovan's transition voodoo magic, every Bulls game would be a track meet. If the Bulls could get more stops on defense, their elite transition attack would get more opportunities, juicing the offense as well as their defense. Swapping Vuc out for Ex-Bull Daniel Gafford would be a godsend. It would cost them Coby White, but with his questionable fit next to Giddey and his looming extension, the Bulls should bear that cost. Klay and Hardy are contract fillers, though Klay's shooting gravity and Hardy's age ensure they aren't zeroes.

Mavs:

Dallas has two motivations to make this deal. The Mavs were light on legit guards even before the Kyrie injury, so Coby White would fill a short term need. His movement skills, handle, and shooting versatility would help the Mavs tread water on offense. Long term, those same skills fit nicely next to the Kyrie-Flagg-AD-Lively quartet. Any defensive issues that an Irving-White backcourt present are trivial with potentially generational backline Dallas can trot out. The second motivation is admittedly a bit unserious, but if AD insists on being a power forward Nico should at the very least try to get a shooting center. Vucevic is old and expensive, but he's on an expiring contract and can be a productive offensive hub off the bench. His terrible defense matters less with AD/Lively/Flagg flanking him.