++Notes:++
I know that Giannis isn't leaving this offseason and that Fox can't be traded for 6 months, however if things go south after then this could be a potential trade package. (More or less picks could be added/taken away from this deal!!!)
++Reasoning:++
++Bucks:++ Get a solid return for Giannis, which includes good young players and multiple picks for them to kick-start a rebuild. They could trade guys like Kuzma and Bobby Portis for more capital and players, and begin a new era of Bucks basketball.
++Spurs:++ They recently signed De'Aaron Fox to a massive extension which many have called an overpay. What if they don't sign him to play him, but to trade him for a star? They get Giannis and unleash the most dominant frontcourt pairing in NBA history, and utilities Victor Wembanyama's (potentially) small prime (injuries hit different at 7'7").
++Conclusion++
Both teams get a new direction, Bucks get a fresh start, Spurs get MUCH better in the most competitive western conference of all time. As I said at the start you could add or remove picks/players from the deal as it is only supposed to be the framework.
GOD BLESS!