They also can call RT (realtime) Kernel or in case of Arch that’s pretty much Zen, but in absolute most cases you don’t really need it, unless you have room full of midi hardware for music production or stuff like that though…
Usually it is enough to just:
Run as:
perl ./realTimeConfigQuickScan.pl
Use this script and all of it’s recommendations (except maybe CPU Governors & RT Kernel), then reboot
Towards the middle. You should read the whole thing for better understanding of what you are trying to do.
Edit
The reason you can’t find it in pamac is because those kernels are aur packages and unless you have aur support enabled in pamac you will not see them. Installing kernels via pamac is not recommended. Do it in a terminal or better yet in a TTY