I have a new Apple TV 4K (2022 third generation) and a Sonos Playbar. Despite setting the Apple TV to use IR, rebooting the ATV remote and going through the Sonos TV setup, I cannot reliably control the Playbar volume. Each time I turn the ATV on, I can only decrease the volume; if I visit the ATV Remote settings, I can increase the volume and use the mute button. The remote is certainly working as pressing the volume up button flashes an LED on the ATV - it’s just not being reliably recognised by the Playbar.