The ATV 4K remote does not sent IR codes for anything but volume and mute. These are sent as IR to support displays that don't have HDMI CEC control.

Everything else is bluetooth. If you tried using a cell phone camera, you'd have seen no IR when pressing home, and other functions and would have saved yourself lots of time.

Fortunately, Apple still supports IR codes on the main unit and based on their previous remotes, the codes have been deciphered.