iPhone XR went black

My iPhone XR (only a couple of months old) just went black. It was on about 20% battery and then it just died out of nowhere. It's been on the charger for over an hour, but nothing! I tried to press and hold the volume down + power button, nothing. I tried pressing volume up, volume down, and then the power button for like a minute. Nothing. If I connect it to my computer (macbook) iTunes can't find it. Any ideas what I can do that doesn't require bringing it in?

Thanks, and have a great weekend everyone!

Hannah