No, this doesn't at all sound like a predatory loan: https://www.espn.com/college-football/story/_/id/38335229/florida-legislator-says-bears-dt-gervon-dexter-nil-deal-violated-law
TLDR: Dexter signed an NIL deal with an investment capital company, "Big League Advance", where they agreed to pay him just under 500k in exchange for his likeness rights that year, but they included a clause later in the contract that Dexter would owe them 15% of all NFL earnings over the next 25 years in exchange.