Then you have your very “picky” old nvidia GPU which works only with a specific old nvidia driver and if you try to install anything else, there will be a conflict.
I just use TKG's installer, it's pretty much fixed all of my NVIDIA-related problems:
git clone https://github.com/Frogging-Family/nvidia-all
cd nvidia-all
makepkg -si
The default is vulkan-beta drivers via DKMS. You may need to manually install linux-headers but you may already have it installed from other DKMS-related activities.