I see this got fun real quick lol. So you don't have a camera ic but rather a camera ldo (low drop out/off). This regulates voltage to both cameras and is usually the culprit if both and only if both cameras are not working.
As for it being the proximity/front camera I highly doubt thats the case. Almost always the front camera, if damaged, will short the phone into a red screen/reboot. Rear camera rarely causes this to happen.
If your camera ldo is damaged or not making proper contact with the pads underneath both cameras will not respond.
Honestly let me get a few more beers in me and I'll make a quick video to show you lol.