Hi CMATH1989,
Thanks for contacting Apple Support Communities!
We understand that you're unable to adjust the volume of your Sonos Arc.
Check out this resource which covers how to troubleshoot the volume buttons not working: If the volume buttons on your Apple TV remote stop working - Apple Support
- "Press and hold the TV/Control Center button
and the Volume Down button
at the same time. Hold the buttons down for about 5 seconds, or until the status light on your Apple TV turns off and on again. - Release the buttons. Then wait 5 to 10 seconds for a Connection Lost notification to appear on your TV screen.
- Wait while your remote restarts. When the Connected notification appears, you can use your remote.
Learn how to control Apple TV with iOS or iPadOS Control Center.
If you still need help, contact Apple Support."
Take care!