How to use a Youtube channel live url to embed and autoplay. Instead of Video ID that has to be constantly updated for live stream changes.
I mixed two sets of code and came up with a working auto play Youtube video embed from a channel live stream.
My thanks to both of the other contributors for their help. Hopefully this helps someone else some time.
Example stream
https://www.youtube.com/embed/live_stream?channel=UCwobzUc3z-0PrFpoRxNszXQ
The code below by Zubi answered Nov 25 '16 at 7:20  works with Youtube videos.
With code by Darien Chaffart found at
https://stackoverflow.com/a/61126012/1804252
Example
<html>
<head>
</head>
<body>
<center>
<script src="https://www.youtube.com/iframe_api"></script>
<!-- Insert Livestream Video -->
<iframe id="live-video" src="https://www.youtube.com/embed/live_stream?channel=UCwobzUc3z-0PrFpoRxNszXQ&enablejsapi=1" width="100%" height="100%" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen enablejsapi="1"></iframe>
<!-- Basic API code for Youtube videos -->
<script>
  var player;
function onYouTubeIframeAPIReady() {
  player = new YT.Player('live-video', {
    events: {
      'onReady': onPlayerReady,
      'onStateChange': onPlayerStateChange
    }
  });
}
function onPlayerReady() {
  var url = player.getVideoUrl(); /*Use Youtube API to pull Video URL*/
  var match = url.match(/[?&]v=([^&]+)/);
  var videoId = match[1]; /*Use regex to determine exact Video URL*/
  // Insert a new iFrame for the livestream chat after a specific div named chatframe*/
  var livevid = document.createElement("iframe");
  livevid.src = 'https://www.youtube.com/live_chat?v=' + videoId + ''
  livevid.width = '100%';
  livevid.height= '100%';
  document.getElementById("chatframe").appendChild(livevid);
}
    function onPlayerStateChange() {
    }
    
    function onPlayerReady(event) {
      event.target.playVideo();
    }
    // The API calls this function when the player's state changes.
    //    The function indicates that when playing a video (state=1),
    //    the player should play for six seconds and then stop.
    var done = false;
    function onPlayerStateChange(event) {
      if (event.data == YT.PlayerState.PLAYING && !done) {
        setTimeout(stopVideo, 90000000);
        done = true;
      }
    }
    function stopVideo() {
      player.stopVideo();
    }
       
</script>
</center>
</body>
</html>