I just tested the lag on my live view, out of curiosity, on a camera that takes the longest time to invoke live view. Many seconds, because I thought doing it with the worst of them might also result in the worst live feed lag.
Granted not very scientifically, or precisely, though trying to count once per second, for a rough feel. I could distinctly hear what I said being repeated from the phone. For example, as I got to the pause between 7 and 8, waiting to say 8, I would hear the phone say 7, right in the middle, then I would say 8, and I would hear that in the pause before 9, etc, which to my way of thinking puts the lag at about 0.5 seconds.
Not easy to do, as the feedback soon builds up, but you do get to hear what you say before that happens too badly.
Maybe because I am on European servers, don’t know, but my delay on live feed is half a second. Not sure where your bits go to hang out for so long.