So within both 19.12.2 and 19.12.3., YouTube Streaming simply DOES NOT work.. either via the connected YouTube Account or Custom Stream.
What happens is when I hit "Go Live"., the Stream Prepares > Starts > Ends all within the span of a 1s … YouTube itself (in the "Stream Health") never indicates that it even receives a connection attempt.
As a result of this I have to keep Rolling Back to 19.12.1., as at least the Custom Stream was working with the new YouTube Streaming Service... but this does mean that should I want to Stream, then my only options at present at Twitch (which I never use) and Mixed (which it's better to use Xbox DVR for)
I mean I'm also having some notable issues with Twitch and Mixer, as regardless of settings there is A LOT of Data Corruption that happens frequently with Streams being displayed... and Mixer also seems to be a little hit-and-miss if the Stream is actually being sent.
Later today I'm going to be taking a closer look in the Admin Panel for Windows Firewall as well as some experiments using the different Display Drivers with both the 2019 and 2020 versions of CNext., as I have a feeling the issues are entirely with CNext 2020 and not the Drivers themselves.