Hey Srose611,
We'll be happy to help look into the unresponsiveness you're experiencing on the iPhone XR and the cellular data connection issue with you.
If you're still unable to restart or start up as expected you may have to place the device in recovery mode. Keep in mind you can try placing the device in recovery and reinstall the iOS software keeping your data intact. Take a look at the article below.
If your iPhone, iPad, or iPod touch won't turn on or is frozen
Once you have access to the device you can check for a carrier update to help isolate the cellular connectivity issue. Resetting your network settings may help as well. Keep in mind this also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before.
If you see No Service or Searching on your iPhone or iPad
Keep us updated once you're able to give all these steps a try.
Cheers!