It should be possible to implement something like that on the phone side 👀
Discussion
Yeah! STT<->TTS have gotten a lot lot better recently.
It would feel like you are using walkie talkie, but it’s simulated.
Heck new iPhones have the ability to synthesize your own voice.
So imagine having your partners voice setup on your phone and vice versa. It would be as close as walkie talkie can be.