Apple TV 4K now offers several distinct approaches to hard-to-hear dialogue. During playback, open the audio options and choose Enhance or Enhance More; Apple says the stronger setting may alter the intended sound mix. An Isolate option can be enabled through Accessibility settings for maximum voice clarity.
This is a particularly useful experiment with a television and Sonos soundbar: play the same difficult dialogue scene, switch between the settings and listen for clarity without harshness. Do not change every audio option at once, and remember that a soundbar may apply its own processing.
What to do: on Apple TV 4K running tvOS 27, test one dialogue-heavy scene at normal volume and decide whether Enhance or Isolate helps. Apple’s official guide provides the current options rather than relying on old menu screenshots.