NO BATTERY ICON LISTED!
A SOFTWARE UPDATE CAUSED THE BATTERY ICON DISAPPEARED!
iPhone 12, iOS 15
Question marked as
Yes, it is triggered by an update but that is not the cause of it. Since the iPhone has an ingenuine battery all the functionality may not be available.
Parts and service history
With iOS 15.2 and later and iPhone XR, iPhone XS models, and later—including iPhone SE (2nd and 3rd generation)—you can go to Settings > General > About for the parts and service history of your iPhone. You can also find out if the battery has been replaced. If the replacement was done using genuine Apple parts and processes, "Genuine Apple Part" will appear next to Battery.
Do you have a disabled Face ID alert on your device?
Please read the "What to do Next" section in this link, if nothing works as per the instruction given in this link --> If an alert says Face ID has been disabled on your iPhone or iPad Pro