apt – Cannot load NVIDIA driver (Ubuntu 21.04)

I am having issues loading the NVIDIA driver on Ubuntu 21.04. The result of nvidia-smi is

NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver. 
Make sure that the latest NVIDIA driver is installed and running.

And the result of nvidia-settings:

ERROR: NVIDIA driver is not loaded
ERROR: Unable to load info from any available system

I have tried reinstalling the latest NVIDIA driver available, 470.57.02 (my current kernel is 5.14.2-051402-generic). When installing with sudo apt-get update && sudo apt-get install nvidia-driver-470 I get this error:

    INFO:Enable nvidia
    DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/put_your_quirks_here
    DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/dell_latitude
    DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/lenovo_thinkpad
    Loading new nvidia-470.57.02 DKMS files...
    Building for 5.14.2-051402-generic 5.14.3-051403-generic
    Building for architecture x86_64
    Building initial module for 5.14.2-051402-generic
    ERROR (dkms apport): kernel package linux-headers-5.14.2-051402-generic is not supported
    Error! Bad return status for module build on kernel: 5.14.2-051402-generic (x86_64)
    Consult /var/lib/dkms/nvidia/470.57.02/build/make.log for more information.
    dpkg: error processing package nvidia-dkms-470 (--configure):
     installed nvidia-dkms-470 package post-installation script subprocess returned error exit status 10
    dpkg: dependency problems prevent configuration of nvidia-driver-470:
     nvidia-driver-470 depends on nvidia-dkms-470 (= 470.57.02-0ubuntu1); however:
      Package nvidia-dkms-470 is not configured yet.
    dpkg: error processing package nvidia-driver-470 (--configure):
     dependency problems - leaving unconfigured
    Setting up libnvidia-encode-470:amd64 (470.57.02-0ubuntu1) ...
    No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                              Processing triggers for desktop-file-utils (0.26-1ubuntu1) ...
    Processing triggers for gnome-menus (3.36.0-1ubuntu1) ...
    Processing triggers for libc-bin (2.33-0ubuntu5) ...
    Processing triggers for man-db (2.9.4-2) ...
    Processing triggers for mailcap (3.68ubuntu1) ...
    Processing triggers for initramfs-tools (0.139ubuntu3) ...
    update-initramfs: Generating /boot/initrd.img-5.14.3-051403-generic
    Errors were encountered while processing:
    E: Sub-process /usr/bin/dpkg returned an error code (1)

I have tried purging all NVIDIA packages with sudo apt-get purge nvidia-*, sudo apt-get autoremove and repeating the process, but no success. I also tried installing it on a previous kernel (5.11), installing a previous driver (nvidia-driver-460), but nothing worked.

The card is correctly detected. This is the output of lspci | grep NVIDIA:

01:00.0 VGA compatible controller: NVIDIA Corporation GA106M (GeForce RTX 3060 Mobile / Max-Q) (rev a1)
01:00.1 Audio device: NVIDIA Corporation Device 228e (rev a1)

I also have tried the solutions from https://askubuntu.com/questions/951046/unable-to-install-nvidia-drivers-unable-to-locate-package, and https://askubuntu.com/questions/927199/nvidia-smi-has-failed-because-it-couldnt-communicate-with-the-nvidia-driver-ma, still no success.

Any advice? Thanks!