Why won't dualshock4 charge (hardware repair)?

To preface, it is not the PS4, I have other controllers that connect, charge, and play just fine.

This controller had been opened before (new thumbsticks and triggers) but after years of use it all of a sudden wouldn't charge. I bought a new USB charging port socket board and 12pin flex cable (yes, it's the same model) and replaced that. Still nothing. So I took a good charged battery from a different controller and put it in this one, it powers and plays fine but still won't charge. The connection is there though with charging port socket board as the controller light works. So if it's not the battery and it's not the charging port.. what is the problem? Oh, and while it won't charge, occasionally when I've tried to charge it I will get a “too many USB devices connected” prompt. And again, it's just this controller. Others work fine..