Out of the box, it's kind of weird, the DX11 allows me to change to 1920x1080 resiution and allows me to change my refresh rate to 120hz, while wayland only allows me to change to 1920x1080 with no indication of refresh rate.
This is on 5.11 with some mild flickering.
So for 5.8.050800-generic: the screen starts flashing on both DX11 and Wayland, it is even during the boot session. It looks almost like there is a bad reception on an old television if that makes sense?
On 5.8.0-69-generic, I am stuck at 3840x2160(16:9) with no refresh rate mentioned. The screen tearing howevere is COMPLETELY gone, no issues whatsoever, however my bluetooth and network function have become unusable. same goes for the touch screen. This is on DX11 I think because I can't select wayland
The usual way to correct that woud have been to give the TV a sharp hit on its side panel
Where you can select refresh rates, have you tried much slower refesh rates than 120Hz or even 60Hz?
Clearly your problem is not fixed, so it would be a good idea to undo the "Solution" marker in your post above (think it was around #11 or #12). This may then attract more forum inmates to look at this thread.
The weird thing is, that I only have a small selection of changes I can apply, and they all give screen tearing when moving the mouse. However, the higher the screen resolution, e.g. on 120hz the fewer the tears appear
The selection is also very weird:
1920x1080 = 120,02Hz - 119,94Hz - 59,96Hz and finally 59,96Hz
They seem really off, no?