After a year of trying to figure out why I would have 1 or so seconds of complete sound drop when watching atmos content every 10-25 minutes, I found a thread that fixed it. Setup is a Samsung Q80, Apple TV 4K, Sonos Arc/Sub/Ones. In the Apple TV 4K, turning off match frame rate made the sound drops go away. From what I read, when/if the frame rate reconciles the sound drops. Hopefully this helps others as it took finding the right thread to fix it a year later! Good luck all!