If KC is purely evaluating a business decision, it might be a better play to stay at Tennessee for another year than go pro this year- here's why:
If you believe mock drafts right now, KC is somewhere between 28-40 (2nd round picks, after pick 30, are not guaranteed anything).
IF HE GOES:
For purposes of this, let's assume KC is drafted 30th, which is the end of the first round right now. What he would make is locked in based on the NBA Rookie Pay Scale (see above)
He would make $1.68 million in year 1 and it goes up every year to $3.3 million if his option is exercised in Year 4.
After 4 years (2022-2026), he would have made $8.5 million.
IF HE STAYS:
Let's assume KC progresses after an offseason with Barnes, balls out next year, and plays himself into a lottery pick.
Based on the rookie pay scale, the 14th pick (last lottery pick) makes $3.4 million in year one and it goes up to $4.8 million in Year 4.
After 3 years (2023-2026), KC would make $9.35 million. That's $800k more in the same amount of time as going wearly. That also assumes KC makes zero NIL money while coming back to UT for his sophomore year.
TL;DR- if KC wants to make a good business decision, it makes a lot of sense to come back, especially if he gets a huge NIL deal to do so.
