The new tvOS features are worth exploring if Apple TV is a regular music source. But the format received by a sound system depends on the actual output chain; seeing a high-resolution label is not the same as confirming it at the speakers.
With Sonos in the house, a controlled listening comparison is more useful than buying new hardware on the promise of better sound.
Action: check tvOS and Apple Music audio settings, then compare one familiar track through the existing TV path and a direct Sonos source at matched volume.
