iPhone XR screen is not turning on at all.

Even with pressing the volume up and down then side button for at least 10 seconds, my iPhone XR screen is not turning on at all - it doesn't even show black. a couple minutes ago i put it in the charger, and it showed the red battery icon, and that was it. hasn't turned on since. i put the charger on another iPhone to make sure it works, which it does. any help?