Given the fact he has so much unfinished business now and would be the face of college basketball in 2020-21, along with the fact his family is well off, and along with the fact international basketball may still be off the table for another 12-18 months due to COVID-19, I just don't see Garza leaving a potential top 5/10 team to not play in the NBA as a reserve (best case scenario) or be in the G-League next season (likely option). There is no scenario I see that results in Garza being drafted higher than the 2nd round and seeing minutes in the NBA next year. So if money isn't a concern, what's the rush? Try to do something special.
Former Indiana 7-footer Cody Zeller left Indiana early, was drafted 4th overall (much higher than Garza could ever hope to be drafted) and has averaged 8.2 ppg over his career. Bet if you asked him now, he'd say "Stay in college if your family doesn't need the money today."