Price and Availability
4th Gen features Siri AI

Essentially users can ask Siri AI questions to either find a new show or movie or learn more about a title. Apple gives the example that you can check whether something is appropriate for a 15-year-old or ask where a TV series was filmed. Plus when paired with an Apple Intelligence-enabled iPhone, Siri AI can tap into your personal context and answer questions like “play the series my friend recommended”.
4th Gen offers hands-free voice control
Although the 4th Gen remote looks similar to its predecessor, it also benefits from Find My support that plays a sound on the remote when lost too.
4th Gen can pair with up to four HomePod Mini 2s for a surround sound experience

4th Gen promises faster navigation and better responsiveness
The A19 chip also includes a new AV1 decoder which Apple promises “more efficient, high-quality streaming” while using less bandwidth.
Both can be used as smart home hubs

However, as it benefits from Siri AI built-in, the new 4th Gen model now supports automations, guest mode and enhanced with Apple Intelligence-generated camera activity video descriptions and summarised notifications too.