FWIW you can use the Steam UI to configure any controller if you launch big picture mode on desktop. I've used it to remap my Stadia controller and an Xbox controller and it works almost as good as the Deck configuration.
I say almost as good, because the "Steam button + joystick" mouse controls don't work for very long; the Xbox button gets mapped to the Steam button, but holding that will turn off the controller...
Oh awesome. I suppose you can also do the menu overlays? Obviously there's no track pad to put them on but I imagine could work well mapped to eg a left joystick.
I say almost as good, because the "Steam button + joystick" mouse controls don't work for very long; the Xbox button gets mapped to the Steam button, but holding that will turn off the controller...