GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
Did you Reboot after switching Drivers? If So:
Let's try setting the mode:
If connected by HDMI:
xrandr --addmode HDMI0 1920x1080_60.00
Or
xrandr --addmode HDMI1 1920x1080_60.00
If by Display Port:
xrandr --addmode DP0 1920x1080_60.00
xrandr --addmode DP1 1920x1080_60.00
I restarted the system after changing Drivers.
And the commands don't work, i get this result:
xrandr: Failed to get size of gamma for output default
xrandr: cannot find output "HDMI1"
This can depend on which port you are plugged into. Some cards have up to four.
I tried HDMI0 to 4 and DP0 to 4 but still nothing.
I went also to settings to About and i saw that in Graphics it said "llvmpipe (LLVM 12.0.0, 256 bits)" could this be the problem?
Hmmm... still looks like it is not using your Nvidia driver...
if you tap alt+F2 and enter in nvidia-settings, does it offer you the Nvidia XSettings Window?
Yes, but i see nothing in there
Can you please expand on this? Nothing in there in regards to resolution? Or nothing at all?
I mean that the app is empty, that's what i see:

Definitely looks like Nvidia is not installed.
Output of:
ubuntu-drivers devices
I typed this command to terminal and i got:
vendor : NVIDIA Corporation
model : GM204 [GeForce GTX 970]
driver : nvidia-driver-418-server - distro non-free
driver : nvidia-driver-510-server - distro non-free
driver : nvidia-driver-450-server - distro non-free
driver : nvidia-driver-390 - distro non-free
driver : nvidia-driver-470-server - distro non-free
driver : nvidia-driver-470 - distro non-free recommended
driver : nvidia-driver-510 - distro non-free
driver : xserver-xorg-video-nouveau - distro free builtin
What does this yield:
sudo apt install -f nvidia-driver-470
It's completed, do i need to restart my PC?
Yep, let's test...
Hi, sorry that you needed to wait long.
I restarted my system and i still have these issues. And on settings it says still that my graphics are "llvmpipe (LLVM 12.0.0, 256 bits)"
In your BIOS EFI settings, Secure Boot must be disabled.
Please check that it is and disable it if it was not. Then reinstall the Nvidia-Drivers and test.
I powered off my PC but i forgot to press the F2 key to enter BIOS, but when i booted up to Zorin i saw that the screen was changed into 1920x1080, but the screen is still flickering and the second screen isn't showing. Maybe i know why my screen is flickering because my monitor is a 120HRz monitor and maybe the system is at 60HRz?
It's certainly possible. Why not change your refresh rate and test it out?
but how? i still can't change it on settings.
If xrandr isn't working...
xrandr --output HDMI1 --rate 120
You can configure the .xml file ~/.config/monitors.xml
Open it with Text Editor.
Look for
<width>1920</width>
<height>1080</height>
<rate>60</rate>
Change rate to 120
Save and exit, log out and in or reboot to test...