I love this feature on Prime Video, I wish Apple would implement it system wide, especially because I'm not subscribed to TV+.
Tested it a little bit with the beta 1 at a friend house today.
The good:
A)It is indeed implemented system wide (Settings/Video and Audio/ enable "Enhanced Dialogue"), and works with any audio hardware, including Bluetooth paired stuff and even tv´s internal speakers. So is no longer a Homepod exclusive feature.
B). It works much better than before, probably thanks to the AI/machine learning stuff. So much better, in fact, that I would consider it a game changer. There are two modes now within the feature: standard and boost, which make voices even louder.
The Bad:
Unfortunately, this improved version of the "Enhanced Dialogue" feature does not work on the Apple TV 4K first gen (2017), I guess because the A10X chip is not good enough to perform machine learning related routines.
The Surprise (Bonus):
tvOS and IOS 18 added spatial audio support over Airplay 2. This means, for example, than you can pair a stereo pair of Sonos Era 300 or a stereo pair or Amazon Echo Studio´s with an Apple TV 4K and enjoy Dolby 5.1/7.1 and Atmos content from tvOS apps.
Right now, with tvOS 17, regular Airplay is limited to stereo and the only way to get surround sound wirelessly with the Apple TV 4K is by using big Homepods in Home Theater Mode (which is not Airplay) or using Bluetooth implementation of spatial audio over headphones, which require Airpods that support the feature.