On the wiki there are instructions to install obarun from arch, basically the procedure is similar. but easier. Use it as a guide.
You adopt the obarun pacman with the obarun pacman.conf, incorporating the obarun repositories.
You install the obarun-keyring and pacman, manually adopt the /etc/pacman.conf.pacnew (as in the wiki)
Basically you add obcore into pacman on top of arch's core
[obcore]
SigLevel = Never
Server = https://repo.obarun.org/obcore
Run pacman -Sy
pacman -S obarun-keyring pacman
pacman-key --populate obarun archlinux
then move pacman.conf.pacnew into pacman.conf
pacman -Sy
to adopt the new repositories
Remove systemd and systemd-libs (and possibly netctl if it is installed) - you must force it, (pacman -Rdd ), you don't have to remove anything that shows dependency to it, just those 2 or 3 packages. Check for netctl if you have it.
Then install base with this new pacman, that will also upgrade essential arch software to obarun sw (higher edition), but that is not all. When you are done upgrading, things may seem ok but are not.
You must run pacopts origin /pacopts origin obextra / pacopts origin obcommunity, the most important is the first run since it is dealing with obcore packages. It scans all installed sw and shows you a list that DID NOT come from obarun and should, since they need systemd/-libs
THEN, you create boot, root, and user trees depending on your needs (look up the wiki the introduction, and also the installation from arch - basically 4-5 commands and you are done.
Bootloader (syslinux and grub are supported), better rerun the setup, obarun's linux line should have ro instead of arch's rw.
You can reboot.
There were 2-3 conversions on sysdfree.wordpress.com but obarun repositories and the service setup was different then.
It is not generally advisable to do conversions but for an experienced "arch-based" user it shouldn't be too hard.
You were in artix a while ago, weren't you? Nous had published a script for making the conversion, but due to variability of setups those things may not always work for a long time or for every situation.
Welcome
PS Since I keep an extensive cache collection and don't have to download anything, I can do this in 15'.