Yes, for comparison take the major US pro leagues. They all have salary caps as part of a collective bargaining agreement, but athletes can earn any amount in endorsement deals with third parties, and that doesn't count against their team's cap.
With the pros it's perhaps not a big problem. Maybe it would be rare for company X to offer athlete Y a deal that's contingent (perhaps not openly) on the athlete playing for team Z. At least rare to do it so blatantly that other teams would contest it as effectively a salary cap violation or CBA violation. But with college athletics it seems likely to be a problem.
With the pros it's perhaps not a big problem. Maybe it would be rare for company X to offer athlete Y a deal that's contingent (perhaps not openly) on the athlete playing for team Z. At least rare to do it so blatantly that other teams would contest it as effectively a salary cap violation or CBA violation. But with college athletics it seems likely to be a problem.