How to use the volume control on my remote device
I cant control the volume from my AppleTV+ remote device
Apple TV, tvOS 14
Hard to answer without knowing if you have audio from TV or AV Receiver or Soundbar, but I will give it a try.
When Apple TV cannot use HDMI CEC for Volume Up, Down and Mute it will use IR instead and you can have Apple TV learn IR codes from your AV Receiver remote or Soundbar remote or TV remote. See below.
1. Go to Settings App > Remotes and Devices > Volume Control.
2. Select Learn New Device…
3. Follow the onscreen steps to program your Siri Remote to control volume for your Soundbar. Make sure you use the original device remote (not Siri remote) for the onscreen Learning.
Make sure under Settings > Remotes and Devices > Volume Control, the device you just learned is selected.
Volume + - or Mute not working - IR Trouble Shooting for Siri Remote
Source: New Apple Siri Remote 2021 Owner’s Thread + FAQs + User
