Welcome Community,
The script which we provide will auto detect your CPU march and if your system supports v3 optimizations, it will automatically add them so that you pull in packages which are optimized and more secure when you update!
The following script will also backup your pacman.conf.
Run the following Script:
wget https://mirror.cachyos.org/cachyos-repo.tar.xz
tar xvf cachyos-repo.tar.xz
cd repo
sudo ./cachyos-repo.sh