Thank you very much i already found a "generic solution", taking this code from grub repair tool, work for every main linux system: if root is in /dev/sda1
sudo mount /dev/sda1 /mnt
sudo mount --bind /dev /mnt/dev
sudo mount --bind /dev/pts /mnt/dev/pts
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
sudo chroot /mnt
Then,
pacman -Rnsc nvidia-dkms nvidia-settings nvidia-utils
After booting you will have nouveau again, but if you really need the nvidia-470 driver, just do:
yay -Sa nvidia-470xx-dkms opencl-nvidia-470xx nvidia-470xx-utils lib32-opencl-nvidia-470xx
Last but not least the nvidia-settings package can be the latest from extra repo, so simple do:
yay -S nvidia-settings
Listing all nvidia packages:
pacman -Q | grep nvidia
nvidia-470xx-dkms 470.82.00-1
nvidia-470xx-utils 470.82.00-1
nvidia-installer-db 2.5-1
nvidia-installer-dkms 3.3.10-1
nvidia-settings 495.44-1
opencl-nvidia-470xx 470.82.00-1
Since from now on you will update your Nvidia LTS Legacy driver from aur, is good to ignore this endeavour script in /etc/pacman.conf (To avoid future warning)
IgnorePkg = eos-kernel-nvidia-update-check nvidia-installer-dkms nvidia-installer-db
I think removing nvidia-installer-db && nvidia-installer-dkms is safe for reasons explained above. 