Siri unable to adjust Apple TV volume
When I ask Siri to turn volume up or down on apple tv she says I can control the volume through the remote. She will not adjust the volume.
[Re-Titled by Moderator]
Apple TV 4K, tvOS 18
That is as intended. The volume is controlled on the TV or separate audio system, not on the Apple TV box. So it is outside of what Siri can do for you (unless you have Apple HomePods).
See here what Siri can do for you: