sudo mhwd -r pci video-nvidia-470xx-dkms
sudo mhwd -r pci video-nvidia-390xx-dkms
Then post the output of
pacman -Qs nvidia
sudo mhwd -r pci video-nvidia-470xx-dkms
sudo mhwd -r pci video-nvidia-390xx-dkms
Then post the output of
pacman -Qs nvidia