HDMI not responding, NVIDIA, Ubuntu 18.04.3 fresh install

[CatKiller]

It's probably worth trying KDE if you're using Gnome (or Gnome if you're using KDE).

You may have hit the limits of the underlying framework, with X, KMS, Optimus being a nightmare, and so on, but it's possible that your flickering is only exposing a weakness in the desktop environment layer. Gnome and KDE have independent ways of handling that.

It's something to do while you wait, anyway.

[Midnight_Sun]

Cool advice! Will look into it. Thx

[Midnight_Sun]

Heureka! (??)

I am afraid to say for sure, since now I feel, nothing is for sure anymore, but:
It seems to work now.

I installed KDE, removed nomodeset. It kinda worked, some screen tearing, but was way better than before.
But the breakthrough is: Login with Ubuntu - Wayland option!

Now that did the trick. I have HDMI, and super occasionally rare tearing, minimal effect.

Thanks for all the input Gents, appreciated!

So final setting:
Kernel: 5.4.2-050402-generic
Ubuntu 19.10
removed nomodeset from grub
And: Wayland!