I am not sure what turning down G league pay had to do with it. It's not like he was offered a two way contract. Those are now pretty good deals.Kofi's making $400,000 in Japan with a lot of tax advantages plus free housing. He turned down Utah's offer to join their G League team. It was clearly time for Kofi to leave. He will always be remembered for the banners he helped bring to the SFC. Thanks for your time as an Illini.
I don't have any inside knowledge, but do hear rumors. It appears he could have earned more than that in NIL money. There is also the value of the UI scholarship and the long-term value of a UI degree.
It also appears he and his family may have been under the illusion he was going to be drafted and get a deal similar to what Ayo got.
From a purely monetary standpoint; I can't say it's clear it all it was time for him to leave.
From a basketball standpoint, he also expressed doubts whether another year or two of college ball would further prepare him to reach his NBA goal. I don't know how playing in Japan figures in that.
Without more Kofi specific information, I can't say for sure if he made the best possible decision. I can say it is clearly not clear. For old school low post bigs in general; I would say stay in school, max out free education, max out NIL -- unless they at least project to be drafted with a two way deal or better; then consider it.