The original poster didn’t ask about Harvard, but about schools with a 30% acceptance rate or better. At Tulane, whose acceptance rate is slighltly below 30%, 38% of students have a GPA below 3.5. That is a lot more than recruited athletes. There is a lot more to the application. Does an unweighted 3.5 put you in the top 10% of your HS class? At some schools it may. What about top 25%? What are your test scores? What does the rest of the application look like?
A 3.5 GPA DOES NOT exclude getting an acceptance for a 30% acceptance rate school, and you don’t need to be an Olympic medalist.