The .5 lense on my iPhone 11 Pro stopped working

I had this issue. No amount of reset/restoring fixed it. I chatted with apple tech support online. They ran a remote diagnostic. They confirmed there was something wrong. They scheduled an appointment for me at my local Best Buy. The tech there ran the same diagnostic test again... "CAMERA ISSUE REAR CAMERA WIDE ANGLE LENS NOT FUNCTIONING, IS NOT DETECTED IN MRI." The fix was a rear camera replacement, which Best Buy had in stock. It took about 45 minutes. It cost $109. I'm disappointed the camera stopped working after less than 2 years of gentle ownership. However, I am grateful that I did not have to mail the phone in. If reset/restore does not work for you, you will need to get your rear camera replaced. There is no other fix if your camera is not detected. Good luck!

Restore the replacement phone to factory, Restore your iPhone, iPad, or iPod to factory settings - Apple Support then set it up as new, not from a backup. It would appear there is something in your backup that is causing the problem, since it returned to a replacement device after you restored your backup. After the factory restore and setting it up as new, test your camera from there and see if it works. If it does, then there is something corrupt in your backup and you cannot use it.

I suggest that you use the Get Support link at the top of the page here to contact Apple Support for assistance. Apple needs to examine your device and they will explain your options from there.