About Camera Matrix From One Image

that’s a projection, it removes a dimension from your data.

you don’t even have 3D points. you have a random stock photo of a random object.

you might be able to estimate focal length from vanishing points/lines in your picture. I’ve never dealt with vanishing points/lines for this purpose.

you can never get absolute 3D distances from a single picture. you will always be left with scale ambiguity.

please get a book on Multiple View Geometry. what you’re asking isn’t a question, it’s a request for a college course.