Low video quality for live TV on https://www.xfinity.com/stream/

Hello, I've been experiencing an issue with extremely poor video quality while watching live tv on https://www.xfinity.com/stream/.  The quality appears to be about 720p with a modest bitrate at best times, but it becomes a really disappointing experience trying to watch sports.  Sometimes it honestly looks like 480p, and while watching NFL games it can be impossible to read the jersey numbers everything is so pixelated.  Sometimes a game is simultaneously available through Amazon or ESPN via the web browser and the difference was shocking to switch back and forth, the xfinity stream was a blocky mess compared to the other options.  I've set the video quality to high and I'm viewing HD channels, and it's been like this for quite a while, many, many months.  

Is there any way to have the https://www.xfinity.com/stream/ video quality upgraded?  What is the resolution and bitrate used on the site for HD channels?  To be honest I hesitated for so long to reach out to support because I thought the stream quality intentional but I thought I'd reach out to see if there might be a fix. 

Thanks for any help you can provide. Have a good day!