Camera not recognised

If you see a message about a non-genuine part, that is discussed in this support document: iPhone parts and service history - Apple Support

An Unknown Part message appears if the part installation is incomplete or if the part:

Was replaced with a nongenuine part

Was already used or installed in another iPhone

Isn't functioning as expected

About genuine iPhone cameras - Apple Support

The phone thinks there is. I guess the sensor could be in error or maybe the issue is small enough so you don't notice it but a feature such as Face ID may not work.

If the suggestions in the documents to which I posted links earlier do not resolve the issue, get Apple to have a look at it. Go to this page to find your nearest Apple Authorized Service Provider (AASP) or Apple Authorized Distributor (AAD) --> Find Locations - Apple

How to make a Genius Bar appointment

1. Go to Genius Bar Reservation and Apple Support Options - Apple

2. Go to "Get hardware help".

3. Select your hardware and continue selecting options requiring replacing parts until you see "Bring in for Repair"

4. Sign in with your Apple ID

have you tried all the troubleshooting suggestions below:

turn off your iPhone then turn back on? Reset settings? Update your iPhone 16.3.1?