I get what you are saying, but, looking at his situation from the outside with so special insight at all, it would be idiotic for him to leave at this time without a solid likelihood of going in the first round, or, at an absolute minimum, near the top of the second. By all accounts he would be projected to have a big year at Wake next year and, with anything close to the expected level of continued development, move solidly into the first round. The difference between that scenario and playing overseas would be many millions of dollars. Sure, you have to put up with one more year of school (horrors!) and likely only high 5-figures to low 6-figures in NIL money, but the payout would be worth it...
So logic would tell me he either (i) got some sort of guarantee from one or more NBA teams that makes him feel comfortable with his future, or (ii) he has no confidence in his ability to develop and make a jump next year, or (iii) he doesn't care about money and would be fine going back to Europe and playing for much less. My bet would be (i).