Black flickering unless anything changes on screen (z18)

[Aravisian]

@Ponce-De-Leon

So, it worked in Live Mode but not after the Installation ... the first Thing here that came to my Mind was the Point that Zorin runs in X11 in Live Mode, if I'm not wrong and when installed, it runs by default in Wayland.

It actually can run in either, but often runs in X11 in Try Zorin.

But in Try Zorin, it is running a squashFS version of Zorin OS from RAM, rather than relying on installed hardware on the drive. In LiveUSB, the graphics stack is run tightly and conservative, whereas once installed, it includes the full init process and grub handoff.

@FSMcas

Intel HD 505 graphics

This should be the i915 driver, supplied by the kernel.

@FSMcas

grub etc as you find on some websites

Can you try these parameters, all at once?
Guide:

[HOW TO] add a grub parameter

There may be times that a user must add a specialized grub parameter in order to overcome an issue. The purpose of this guide is not to provide parameters, as that would be a case by case basis. It is to provide a guide on how to add one. To add a parameter, in a terminal (TTY, Recovery Prompt or Terminal Emulator) run: sudo nano /etc/default/grub Arrow key down to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" and place your parameter within the quotation tags. For example if you are adding th…

Parameters (In your case, do not use nomodeset, just the below):

i915.enable_psr=0 i915.enable_dc=0 i915.enable_fbc=0

It will look like:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.enable_psr=0 i915.enable_dc=0 i915.enable_fbc=0"
Please remember to run sudo update-grub after saving the changes to grub file as outlined in the guide above.
I recommend a full cycle reboot, after.

This is tot disable runtime management, rather than panel self refresh, because since activity wakes the display, I think that i915 is putting the display into low-power state. When you move the mouse, creating an input event, it forces a redraw.