You may eventually be able to use your Android TV as a Bluetooth speaker

Most TVs that run Android TV/Google TV let you connect a pair of Bluetooth headphones so you can watch your favorite content without disturbing others. If you want to do the opposite, that is, use your TV as a pair of Bluetooth speakers for your phone or other Bluetooth-enabled device, then you're probably out of luck. That's because, with some exceptions, most Android TV/Google TV devices don't support acting as a Bluetooth audio sink device. That could change in a future release of the platform, however.

For some context, when two Bluetooth-enabled devices negotiate a connection, they use profiles that define how they should send data between one another. One such profile is called the Advanced Audio Distribution Profile (A2DP). A2DP is the profile that defines how multimedia audio is streamed from one device to another over a Bluetooth connection, ie. Bluetooth Classic Audio.

Android's Bluetooth stack supports both A2DP source (the device that sends the audio) and sink (the device that receives the audio) roles, but both roles cannot be enabled simultaneously. (I've actually tried this myself. If you enable the system properties that control the A2DP source and sink roles, Bluetooth just crashes outright.)

That's problematic, because it means that a device that's defined as an A2DP source can also never act as an A2DP sink and vice versa. You currently have to pick one or the other. There are presumably custom Bluetooth stacks that enable the A2DP source and sink roles to exist simultaneously (which I assume is how the Bluetooth Stereo feature works on OnePlus' Android TVs), but Android's open source Bluetooth stack has not supported A2DP source and sink roles coexisting - until now.

MediaTek engineers have worked with Google to allow the A2DP source and sink roles to coexist. These patches were first submitted late last year, but they were only recently merged into AOSP's Bluetooth stack. A Googler last year commented that this functionality should be "flag protected" because it is "something that Android TV needs", which suggests that indeed, this feature is intended for TV devices.

Since these patches were only just merged, I don't know when we'll start seeing this in devices. Many devices don't even use Android's Bluetooth stack, instead opting for the custom stack made by the SoC vendor or other third-party. However, it's possible that in the future, Google plans to make Android's Bluetooth stack a requirement. The Bluetooth stack was only just made into an updatable Project Mainline module in Android 13. Android TV operates under a different set of rules/requirements, though.

Anyway, without getting too bogged down into details, that's the gist of what's changing in Android's Bluetooth stack. Personally, I think this is a really cool change, as before you'd need to have guests connect to your WiFi network so they can see/connect to your device. Having your TV turn into a Bluetooth speaker would make things much easier for groups to control music.