3rd pick: Amen Thompson
Overtime Elite prospect Amen Thompson is an athletic 6'7" point guard who, along with his twin brother Ausar, is widely viewed as a top-five pick. Amen is regarded for his passing, defensive ability, and for using his size and explosiveness to finish above the rim. It's hard to gauge how much stock to put in his numbers since Overtime Elite plays a lower level of competition, but Thompson excelled. He averaged 16.3 points, 6.2 assists, and 2.4 steals this season and could be even better in the NBA.
Thompson is a talented draft prospect, but his fit with the Spurs is questionable at best. While having a 6'7" point guard has advantages, his shooting is one of his most glaring weaknesses, and some scouts question whether he will even be an average shooter. That could limit both his and the Spurs' offensive ceiling if they were to draft him unless they are confident they can fix his shaky jumper.
There are also questions about whether he would be the best player available. Draft pundits generally regard Brandon Miller as the third or even second-best player in the class. While there are some understandable character questions, passing him over for a player with an evident on-court flaw might not be the best use of the third pick.
Miller comes with on-court questions, such as fit, but he's known for his shooting ability. The Spurs have gambled with a lottery pick, and it came back to bite them. With that in mind, the Spurs should take the best player available.