iPhone X has black screen and will not respond. Full battery. Help!

I charged my iPhone X to full last night. I used it this morning for about 30 minutes. Now my phone has a black screen and appears to be off. How can I fix this?

It does not respond to being plugged into an outlet and my PC does not recognize it when plugged in. I tried a force reset by pressing up and down volume buttons and holding the power button for 30 seconds. I've done this several times. I tried clicking the power button repeatedly and I've tried "Hey Siri". I've asked others to call and text me. Nothing! This phone is a week old and has no known damage. I can't check the software version since the phone is off.

I have an appointment to see an Apple technician, but I don't want to wait that long if possible. Do you have any ideas???