Weird trade, I get it.

Durant only wants to play for Phoenix. A deal with another team who clearly has a better theoretical package would have been done already if Durant wanted to play with that team. That's why Phoenix does not give up much, because they do not have to outbid anyone and they're not going to outbid against themselves and give in to the asking price (which is why I do not expect Mikal Bridges to be a part of a package, although it would not surprise me). I am willing to bet that, unless he changes his preference, Kevin Durant will be a Sun (if traded).

For Brooklyn, they have to pounce on this Donovan Mitchell opportunity, and it seems like he just wants to be home in New York. Whether he gets traded to the Knicks or Nets, I think he just wants to be back home. They can't allow him to go to the cross-town rival, and if they want the best player they can for Durant, this is the only opportunity. Otherwise, they are not going to get a great package unless Durant decides to add Miami or other teams as desired/preferred destinations. His value lowers day by day, and they can't risk waiting and getting a worse package.

Utah enters a long-awaited rebuild. Once Gobert got traded, it did not matter the package; Donovan Mitchell was also going to be on his way out. Get more picks, grab a player who is marketable enough to make Salt Lake City seem like a desirable city (they host All-Star Weekend this year). Get some picks, enter the rebuild (or retool) and build from the first floor.

I see this as most realistic way for Kevin Durant to become a Phoenix Sun (disregard the picks, just for fillers) while Brooklyn receives a package that reaches their asking price.

Durant is not going to go to a place he doesn't want to go, regardless of a lack of a no-trade clause. If he says his preferred destination is Phoenix, he will end up playing for the Phoenix Suns.