Recently a new HP Envy Laptop had no Camera showing in device manager
This is the default behaviour of the inbuilt Private switch , which can be checked at the Head of “Try this First” https://support.hp.com/in-en/document/c03430151
We confirmed the privacy switch was enabled correctly, all drives and firmware up-t0-date using HP Support Assistant
In the end the Computer needed the lastest Intel Graphics drivers downloaded from the Intel site to resolve this!