IT TAKES ABOUT 45 minutes to fix iPhone XR .The digitizer can be replaced after taking the old shattered digitizer off . The power supply needs to be cut off by disconnecting the battery and then the new Lcd needs to be connected to see if it’s functional . Most of the repair techs take the camera flex cable from the old phone only if not damaged. Care is to be taken if it’s taken from the damaged phone so that the face id still works . In case if it doesn’t work then one needs to reconfigure it