In general, I’ll tell you how to generally downgrade the Nvidia version
yay -Rdd nvidia-dkms nvidia-utils
This will remove the packages and not affect their dependencies (after all, I will just change them to others)
Next you need to select which version you need to install and all packages must have the same version
sudo downgrade nvidia-dkms nvidia-utils nvidia-settings opencl-nvidia lib32-nvidia-utils lib32-opencl-nvidia libxnvctrl
And in each one we choose the same version to which we will switch and reboot!