Have you found a fix for this? I ran into this exact same problem. Fixed a loose piece in the camera and now the buttons won't work.
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=== Update (10/18/23) ===
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The entire inside element that holds the lens as well as the sensor was loose. So the lens and sensor wiggled around. I took it apart and put in two small screws and that fixed the issue. At work we have 4 G7s, and theyre all slowly giving out.