photo icon missng

Use App Library to search the Photo app, see -> Organize the Home Screen and App Library on your iPhone

Organize the Home Screen and App Library on your iPhone - Apple Support           

• If you have find the Photo app, tap & hold on the app, then drag to the Home screen & drop it.

👍 With pleasure to be able to help you.

Thank you for your feedback and you're welcome.

One solution is:

Settings > General > Transfer or Reset iPhone > Reset > Reset Home Screen Layout