NVIDIA 470 driver doesn't work after suspending Ubuntu 20.04.3 LTS

I have 2 monitors, a 28" Samsung UE590 and a 24" DELL. After I suspended my desktop, I found that only the DELL monitor is shown, and it was in much lower resolution.

I checked xrandr, but I got:

xrandr: failed to get size of gamma for output default

After some investigation, I managed to get the Samsung UE590 monitor to work, but I have to use the Nouveau (open source driver), instead of the NVIDIA 470 driver to do that. This causes the CPU fan to run loudly every 10 seconds, and also the whole computer is reacting much slower, probably due to incompatible graphics card drivers.

I tried to run:

sudo ubuntu-drivers autoinstall

and there is this error:

WARNING:root:_pkg_get_support nvidia-driver-390: package has invalid Support Legacyheader, cannot determine support level
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies.
 linux-modules-nvidia-470-generic-hwe-20.04 :
Depends: linux-modules-nvidia-470-5.11.0-38-generic (= 5.11.0-38.42~20.04.1) but it is not going to be installed
Depends: nvidia-kernel-common-470 (>= 470.74) but 470.63.01-0ubuntu0.20.04.2 is to be installed
E: Unable to correct problems, you have held broken packages.

After that I tried to use NVIDIA 460 instead of 470:

$ sudo apt install nvidia-driver-460
Reading package lists... Done
Building dependency tree       
Reading state information... Done
nvidia-driver-460 is already the newest version (460.91.03-0ubuntu0.20.04.1).
0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.

And I set the Activities → Software & Updates → Additional Drivers to nvidia-460.

The UE590 monitor is still not displaying anything. It only works when using Nouveau.

I want to know how to use back the NVIDIA driver and also the UE590 monitor as before.

Thanks!

>Solution :

Try removing the existing Nvidia proprietary drivers with these commands:

sudo apt update
sudo apt remove '^nvidia'
sudo apt autoremove
sudo reboot 

before installing the new Nvidia proprietary drivers with sudo ubuntu-drivers autoinstall