This is certainly an odd occurrence, @Kat6! With the two way talk feature working with live view, an answered ring event should have the same results. Checking microphone permissions was a great call. I recommend also ensuring vpn and bluetooth is disabled, as well as trying this two way talk on wifi only, or mobile data only, on your mobile device.
Although permissions sound proper and live view audio works as intended, removing and reinstalling the Ring app is always a good way to ensure the app is optimally integrated with your mobile device. Feel free to let us know how this goes! 