Switch Pro Controller Power Issue?

Hello,

A little while ago one of my two Switch Pro Controllers just outright stopped working. I have taken both apart and have been swapping parts to see if that isolated the problem to no avail. The battery works fine, all connections are seated tightly, no physical damage to any components but it just refuses to show any indication of life. It will not charge or respond to any inputs. Anyone have any leads to where to go from here? My best guess would be a motherboard failure at this point.

Thank you.