I think it all depends on what is in the agreement that Tyrese signed with the Agent. Using #'s others have thrown around if Tyrese gets $400k and the agent gets $100k for marketing Tyrese to schools like Gonzaga, Kansas, Texas, Tennessee, Illinois, etc. then how is Tyrese worse off. Even if the IRS takes $200k, Tyrese still clears $200k to support his family for a year.
IMO athletes would be smart to have NIL agreements with agents be for multiple years. That way if Tyrese isn't NBA ready next spring, he could still remain at school without taking a pay cut.
If athletes like Tyrese are agreeing to use the current agency as their NBA agent, then there could be long-term issues.
I believe some pro-golfers do a similar deal when they start out. They look for "investors" when they first start out to fund their career and then agree to pay back from future earnings. I believe that is what Cedar Rapids Zach Johnson did.