You may want to install the latest version of the Apple TV software (16.3.3)
See here:
https://9to5mac.com/2023/03/06/apple-tv-siri-remote-connectivity-fix/
This disconnection issue would stop sending commands to your TV set, which normally passes those on to your Sonos Arc, Beam, or Amp via HDMI-CEC. If the remote isn’t communicating properly with the Apple TV, it can’t send those commands to your TV set.