I was able to get mine to work. You need to not have it paired to any devices currently. So if you have it setup in the OneLine app. You need to factor reset it (Press Test 3x).
Once it is booted back up I went to the Home app on my iphone and I tried to add accessory. This first ask for a code so I tell it that I do not have a code and it found some local devices. And I clicked on the device. This then asked if I wanted to allow the device to scan the wifi network.
Once it was on the network then HA was able to see it. But it said it was already pairing with another device. So I power cycle the device (pulled the power from it) reinstalled it back in the ceiling and then HA asked me to enter in the code.
Once code was in I am able to use it as needed. It used to be easier but iOS 14 added extra security to it all so device is no longer on wifi network by default so HA can never detect it. But doing above steps I got both of mine working without issue.
You can then go back into the Home app and add in the speaker by itself this will allow you to have a custom name for Airplay 2 so you can actually know what speaker is what.