I have connected by Apple TV on my LG C9 OLED TV. It is connected via HDMI. The TV is connected to Onkyo AV via ARC. While playing a Dolby Atmos enables movie, the AV receiver does not recongnize the output. But while connected the Apple TV directly to the AV, Dolby Atmos gets enabled. Though the HDMI Audio out is set to Bitstream why the AV unable to play Dolby Atmos. Please let me know if I need to make any adjustment in the settings.