Hi scattaway! Unfortunately, that device is not compatible for us to activate it. The only devices that we can activate for our Bring Your Own Device (BYOD) program (new customers activating a new account and brings their unlocked phone from another carrier) are:
iPhone 6 Plus
iPhone 6S Plus
iPhone 7 Plus
iPhone 8 Plus
You can find more details at https://www.virginmobileusa.com/plans/bring-your-device.html. ~AmyM25
So to confirm, one can buy and activate an iPhone XR directly from Virgin, but one cannot activate an unlocked, or Sprint-enabled iPhone XR purchased directly from Apple?