$15k in credit card debt, $25k gift from relative

I have $15k in debt and just received a check from my uncle who passed away. Should I immediately pay off the $15k? They are high interest cards (AMEX PLATINUM). For context I’ve had the card for years but racked up debt after being laid off, stupid, I know. I’ve read that you can ask for a lower payoff amount or for interest to be removed if you’re paying off the cards, however when I call nobody I’ve spoken to says that is an option. I don’t want to overpay but also want to be debt free. I appreciate your help