CachyOS is building kernels for specific architecture levels.
They do so by using compiler flags.
E.g. in a default makepkg.conf
CFLAGS="-march=x86-64 -mtune=generic "
Vs. one that is optimized for znver3
CFLAGS="-march=znver3 -mtune=native "
This has been optimized into buildbots and repository variations and scripts the makes it possible to point and click in CachyOS welcome.
And the CachyOS guys has done an incredible job in building the infrastructure behind this - they fill a gap - a niche - that is great, fantastic 
If you have a system that supports znver3 or znver4 or similar - you can compile an optimized Manjaro kernel - you can even use it side by side with your original Manjaro kernel - selectable from grub.
Here is a short how-to
Install the base-devel meta package
sudo pacman -Syu base-devel
Then copy the makepkg.conf to your home
cp /etc/makepkg.conf ~/.makepkg.conf
Modify the configuration file to use the optimization flags for your system
Then use the script-snippet from Can the "how-to-compile-the-mainline-kernel-the-manjaro-way" be revived? - #15 by linux-aarhus to build the kernel with your optimization.