If he comes back, he's pretty much guaranteed to make 1.5m or more in NIL. If he makes the jump to the NBA (and he does actually gets drafted in the front of the second round), he'll likely get a multi-year deal making less money than that his first year with little or none of that guaranteed (although that's also highly variable, YMMV). So it really depends on whether he exceeds expectations (most 2nd rounders don't), what kind of terms he thinks he could leverage on his rookie contract, and when/whether or not he gets cut (most second rounders eventually do).

All of that is assuming that KOC's evaluation of Ritchie's draft stock is accurate in the first place though.