SA would jump all over that trade but I doubt the Sun would make it. If I were the Sun GM, I would offer Alyssa Thomas and either Alex Bentley, Jasmine Thomas, or Chelsea Gray or their 4th pick. SA gets a starting forward and a starting guard or one with good upside, or a lottery pick in return for their #2.
And the Sun get rid of a log jam at forward, and one of a strong group of young guards, in return for owning the top end of the draft and getting Jefferson, another guard or wing or forward and maybe a trade back to pick up a back-up center/developmental project.