I would not place all your money on it being as simple as a damaged ribbon cable, keep an open mind about wonky motors etc. etc. I am probably in the same boat with a Mavic Mini gimbal.
Unfortunately there is a lot of stuff packed into these gimbal assemblies and it seems that working out what teh problem is or perhaps where it lies, may come to replacing components, one at a time, and testing the whole assembly after each replacement.
They are all over e-Bay. Many are stripped and just the gimbal. However there are some in various stages also, both with and without ribbon cable and video feed cable. I just bought two stripped one's from a guy in Chicago for 22.50 each. Just make sure to verify all axis are tight if you are considering pre-owned. I have purchased used in the past only to find 1 axis to be wobbly from a prior impact. I would never attempt to restore and they cannot be taken apart without destroying. I have tried to remove and replace board that was damaged at ribbon cable connection and found they are permanently assembled and cannot be rebuilt. I could be wrong so if anyone here has the secret to disassemble and put back together without destroying I would love to hear from you.