Hey SM_00,
Thanks for the reply and additional information. We appreciate it! We've got some additional troubleshooting for you.
Verify that PayPal is still an accepted payment method for your location: Payment methods that you can use with your Apple ID
The footnote for PayPal in that article does say you may need to verify with PayPal.
"2. You might be asked to verify your account with the payment method provider." Contact PayPal to verify all is well.
If PayPal advises they are not preventing use with your iTunes & App Store account, we've got something else you can try. Go to Settings > iTunes & App Store > Tap on your Apple ID > View Apple ID > Manage Payments > Tap your payment method >
Verify everything is correct and select Done.
Try your purchase again. If it still isn't being accepted, we'd recommend contacting Apple Support for additional help. Get Support
Thanks!