Just after I upgraded the main ATV to tvOS13, I tried setting up an XBOX One controller, went into BT controllers, pushed the X button and then "sync" button on the XBOX controller, showed up instantly on the ATV. It worked for navigation too! I fired up Skyforce (it even showed controller specific buttons, like "Press A to Start", worked great.
Definitely works, not sure what's happening on your end. Did you follow the same process?