Huh, I just poked around and saw that option on my Pixel 3a.

On the one hand, it might be interesting to try it. On the other hand, at least with the one BT device I regularly use, the current stack works flawlessly...

Android 12, whose developer previews have started.

Source: https://developer.android.com/about/versions/12/overview

It's what Android 12, the forthcoming version, would have been called if they'd kept the letter-based codenames.