My guess is that something related to the headless setup you had changed during upgrade - likely some package got obsoleted and removed. Then you got some default behaviour from the replacement package along with the rest of the setup.
If you don't get the help needed to resolve this here, you should also post in askubuntu.com.
Get out with this noise. This is the same nonsense as "just install Linux" to a person with a Windows problem.
14.04 to 22.04 so far
Why do they want to get rid of people?
Snap
Ignore the noise and go with Ubuntu LTS. When you get comfortable with that, you could try Debian.
You could play it backwards too. Try Debian, if you can't get it to do what you want, wipe and do Ubuntu LTS. But I do not recommend this path if you have no idea what you're doing. People underestimate how difficult it is to do simple things when you don't know how to, no matter how trivial.
2000-and-never
That's an odd request. I'm not a huge fan of video content but there's legitimately good content in video format.
Well I don't know what OP is planning to use it as, but desktop VLC can cast to Chromecast on the LAN for example.
I don't think you can. On the other hand, if you register a Google account, use a secondary user on your phone to login, install the app and activate the Chromecast, I think you can subsequently use it without the Google account. Delete the secondary user once you're done with the setup. You wouldn't have given Google any useful data and you'd have cost them some.
Hot damn that's a large update! Anyone know what's in it?
E: It's QPR2.
This sounds plausible. I have seen a few guides for headless use suggesting disabling the built-in remote desktop feature and setting up xrdp, xvnc or related and then trying to fixup that session.