You've got the wrong approach, but almost the right idea.
De Vere made a copy head for making inter-negatives, copies etc, essentially it's an enlarger head used upside down including the light source, diffuser etc. The camera with a good macro lens sits vertically above it. Rather than using a standard lens an enlarger lens would be better unless you have a macro lens, failing that a standard lens reversed, which ever way you need bellows.
Projecting onto a camera sensor with no lens fitted is asking for trouble with dust etc, essentially the lens will be in the same position but attached via bellows to the camera.
There were of course dedicated copiers like the Bowens Illumitron, these included a dwevice to control contrast via a flashing exposure (not need with digital), they came in differing sizes, some could copy 120 films other up to 5x4, others only 35mm.
Ian