We recommend going to Chichen Itza if you've never been. You can book an excursion out there with the concierge at the hotel or online prior to going. Expect an all day event but it's fun!
The Yucatan peninsula is known for their cenotes! 10/10 recommend doing an excursion to go see one. It definitely doesn't have to be this one in specific (there are thousands of them!) but this is a great option if you're not trying to be away from the resort all day.
We've personally never been here but have heard really good things! There are several different options when booking so do some research to determine what options you want to go with .