Will the Ghost Phone provide the same camera functions as the Google operating system?

The Pixel 7 Pro camera seems to rely heavily on software processing, so I'm not clear on how a change of OS will affect the camera functions. What should I expect in this regard? Especially, the zoom functions.

Camera functions do not change at all, simply the application that utilizes and manages the camera on the device. You'll find the vast majority of the functions that Google has on their camera app are also used for the GrapheneOS camera app.

There are also a variety of different camera applications you can download if for whatever reason you want to use a different one. I swapped to Open Camera, for example, on my Pixel 5 as it had some features the stock app did not. Simply search for "camera apps for pixel 7 pro" and you can dig through options.

Hope this helps.