What to do if iPhone X freezes and won’t power down

It's possible that the system has stalled or that one of the physical hardware buttons has become unresponsive. There's no way to stop the power and force the gadget to restart because the battery isn't removable. Right now, the best thing you can do is wait till the battery is completely depleted. The phone should then be charged for at least 30 minutes before attempting to turn it on.