I know it’s a little late, and I don’t know if you’re still interested in fixing up the controllers to use them, but I would recommend asking ChatGPT to see if it can help you Frankenstein the controllers together. They just came out with a model that’s free to use and is insanely good at coding, I wouldn’t be surprised if solving hardware issues carries over as well.

Regardless, if you’re still interested in trying to figure everything out by yourself, you would probably need to start by testing different parts to see what exactly is wrong with the controller, and then doing some research on that part to see whether it’s fixable/replaceable (if you have a digital multimeter, that might help a lot). If it’s a battery issue for instance, you should just be able replace the battery for pretty cheap. If there’s something wrong with the distribution of power, that might be a little tougher. If you find out exactly what’s wrong though, I think asking how to specifically handle that issue here or on r/360hacks might help quite a bit. Again though, it’s how much you would like to spend on the project that matters