The main problem with moving Jimmy Butler to the Suns is that the Heat do not seem to want Bradley Beal in any move for Jimmy Butler. Additionally, there's no teams that want an aging player on a supermax of his skillset without assets being involved.
In this deal, the Bulls pivot towards a full tank by trading away both Zach Lavine and Nikola Vucevic to the Heat and then buy out the remainder of Beal's contract since they are one of the few teams who have the cap space to be able to absorb this contract and come away with a few 2nds, a pick swap that is very very unlikely to convey, but the prize is the 2031 Suns pick as they will be looking at a 43 year old KD (retired), 42 year old Butler (retired), and a 35 year old DBook. Additionally, Duncan Robinson is an easy player to add to a young up-and-coming team as a floor-spacer that doesn't take a lot of shots.
The Suns give up everything they can possibly give up (2nd apron = no aggregate salaries so they can only give up picks along with Beal) to the Bulls and get Butler who is their last hope at making the Big 3 work.
Miami has shown that they want to continue to be competitive and are supposedly looking for a win-now piece in their Jimmy Butler trade package. Here, they get 2 players that have over-performed this season, Zach Lavine and Nikola Vucevic, who can slot in at their hole at SG and PF, and provides a dynamic punch that will likely make the Heat feel like they can be a competitive 2nd tier team in the East. There are potential concerns with defensive holes in the backcourt and at PF, but Bam Adebayo, Haywood Highsmith, Jaime Jacquez, Nikola Jovic, and others will likely be able to cover up most of their mistakes.