Hi Joseph,
When you can ping the router from the AP then its default gateway is working. Since you are unable to ping the Internet, it’s probably your NAT configuration.
Did you configure NAT and if so, did you include the subnet of the access point?
Here’s an example:
https://networklessons.com/network-services/how-to-configure-pat-on-cisco-ios-router/
Just imagine that one of the hosts is your AP.
Rene