FaceTime Audio calls - audio blocks for listening party

Not sure how to put this in the title but ...

When talking on a FaceTime Audio call, the non-speaking person’s audio is cut, so you can’t have a conversation where both people can say something at the same time. It’s like going back in time, to when radio conversations were one-way at a time and you had to say ‘over’ when you’d finished talking, then wait for the other person to say their bit ... then ‘over’ and so on.

The result is an extremely stilted and difficult conversation.

I’m guessing that the cause is either the age of the iPhone (and thus performance) and the quality/speed of the connection.

The Question though is; can anything be done about it to improve the quality of these calls? What is the actual cause? I had an idea that there is a greater onus on the performance of the equipment of the person initiating a call (video or audio). Is this still true?