on your /etc/pacman.conf just uncomment the following repository
[multilib]
Include = /etc/pacman.d/mirrorlist
You can also try artix multilib
[lib32]
SigLevel = Never
Server = https://mirror.clarkson.edu/artix-linux/repos/$repo/os/$arch
Or go through their repositories manually at:
http://mirror1.artixlinux.org/repos/
I thought you were talking about a whole 32bit installation. Some people like 32bit distributions on 64bit systems. I have heard arguments for and against them. Beware that artix may not be using systemd but they have a dummy libsystemd pkg and elogind (a piece of systemd) in their system.