I am not on Catalina, still on Mojave, and I too am experiencing slowness with 1.18.1.1973. If I have three streams going, watching live TV is a no no. Yet I can fire up the HDHOMERUN Mac app and watch as much live tv as I wish. So it’s not a network issue.
This is what I get when I do anything involving Live TV or DVR. I have attached my logs. I am running Version 1.3.1.916-1cb2c34d of the Plex app for Mac and 1.18.1.1973 for the server.
TV now appears on the Plex player so that’s good. And TV is playing on the web app now so don’t know what happened there. also noticed that the Plex app doesn’t deinterlace TV.
However, I did find a bug; if you click on the play button as indicated in the screenshot, you do not get the intended HD version of the channel you get the SD version of the channel. The only way to get the HD version is to click on the actual play button on the actual show you want to watch.