The Suns need to rebuild, and the spurs are ready to contend, so here is the trade.
Spurs: The Spurs give up Vassell and Barnes, two players who I don't see being a massive part of their future, along with 4 picks(The two the spurs give up will likely not be valuable at all, the 2 from the Hawks will be). They contend immediately. In addition, once Durant retires, they get a massive amount of cap space and flexibility.
Starting Lineup: Castle, Fox, Durant, Sochan, Wembanyama
Suns: The Suns rebuild, getting some valuable picks and a young asset. This would be combined with a booker trade and possibly a Barnes rerouting, could maybe get them more picks back, kickstarting a rebuild.
Starting Lineup: Booker(Likely to be traded), Vassell, Beal, Barnes(Likely to be traded), Richards.
Who says no?