That sounds like a terrible experience. At first glance it also sounds like a hardware issue but updating anything with an Ubuntu base was always painful to me.

It would help if you gave a little bit more info (like logs), without it, this is my blind guess:

• 1, 2 points to a storage drive on your system
• 5 points to your system drive specifically, that some parts of the drive are failing. Although I would expect that to happen with HDDs, not SSD
• 3 has logs, you can switch to the detail screen during the shutdown splash by hitting Esc? Or maybe a different one on Ubuntu, don't remember. Should tell you which service doesn't want to stop (and if it's always the same one, if you check multiple times)
• As for 4 and 6...I cannot fathom how is that happening

Every time someone posts about systemd I just paste in the link to the Tragedy of systemd video https://youtu.be/o_AIw9bGogo and move on

It doesn't matter, just use the right tool for the job (aside if you specifically want to learn)

None of the x11 sessions in any DE were as smooth video output-wise as the Wayland sessions I tried, especially with multiple monitors, they always had various problems and stutter.

That is why I switched to Wayland in the end.

HDMI-CEC out of the box? Does it not lose focus when you turn off/on the TV so keyboard/remote navigation becomes impossible?

They had 6 months of testing with release candidates, although you are not entirely wrong there are bound to be bugs still. Plus this release is almost entirely DB related refactoring, so you are not wrong about the maturity side either.

That's just what you get when you fork a codebase with no care about code quality (hopefully after this it will be in a good place).

1. They have an experimental Wayland session already. It mostly works except for some pretty important stuff...I also haven't seen development on it for a long while.
2. I think this is almost a 100% no.
3. I tried to implement that myself. Making them shorter than the screen is easy. Making them appear above the edge of the screen is hard, but not impossible - the code is in JavaScript and the logic is kind of disjoint across multiple files and stuff depends on panels being at the edge of the screen - I didn't do it in the end because it was too much effort for something I didn't want that much.

I had lots of problems with the previous version when turning the TV off/on while it's running, like losing keyboard access (no focus) until you use the mouse at least once and it updating the display settings every time. Hope it's getting better now.

TBH the keyboard focus issue is happening on most Login Managers and DEs, so it's not really their fault. I will try it out some time, until then I keep using my SteamOS install.

Depending on your TV it might not be enough. I've set it up, but my TV decides my PC doesn't have CEC because it only starts responding after boot, not immediately.