Any way to mute the camera shutter sound on iPhone XR? Lowering the volume and switching it to silent has no effect.

In this case, it is important to know the exact model number of the device. Usually, it starts with the letter 'M'. For example MT002J/A.

The model (MT002J/A -> iPhone XR, Black, 64GB) was built for use in Japan. Unfortunately, the shutter sound can’t be disabled on this device.

Tip: To identify the model number, go to Settings > General > About. You'll see the part number to the right of Model. To see the model number, tap the part number.

All in all, Apple Support is a good way to get additional info on the issue you might be having with your particular iPhone XR.