Now available with the new iOS 14.2 Beta 3, tvOS 14.2 Beta 3, and HomePod software 14.2 Beta 3, you can set a HomePod as the default speakers for your Apple TV. While you could always set it as your speaker before, you’d eventually have to reconnect your HomePod as your Apple TV wouldn’t save the connection.
It’s unclear whether or not this feature will work on the new HomePod mini, as the HomePod comparison page doesn’t check “Home theater with Apple TV 4K” for the HomePod mini. This could also be referring to another feature, however.
Also included in this update is the just-announced Intercom feature. When you open the Home app for the first time after updating, you’ll be presented with a message explaining how to use the feature and walking you through some settings– for example, if you want to only receive intercom notifications while you’re at home or if you want to receive them when you’re anywhere.