I have tried disabling the Desk and Chord configs. But even so, as soon as I turn on my DualShock4 with Steam running, it 'captures' the device so it is no longer visible to other applications outside of Steam. E.G. Retroarch.

Apart from the obvious solution - close Steam - is there anything I'm missing here? I just want Steam to use the controller when running a Steam game, and leave it alone when not.