1 On any arch related board, when they hear the word pamac they want to puke. I believe it came from Manjaro, and as artix came from Manjaro-OpenRC it tried to bring it over with it. I have no idea what endeavour is and since it is using systemd I am not interested. If it didn't I would know about it, like I know about hyperbola, and parabola, and spark (now that is a good systemd for a newbie to be driven back to MS-win).
- Nevertheless, the way pamac displays packages and information is about the best I've seen (including debian's synaptic). But you have to understand that ALL the information/data displayed by a pamac is information fed to it by pacman (and an Aur helper script it incorporates).
2 Obarun's pacman incorporates ALL arch repositories, and therefore ALL Arch packages available. Artix doesn't. And Manjaro has NO ARCH packages available, NOT ONE! AUR is not arch.
3 If you use pacman right, which means no matter what has been done, % sudo pacman -Syy will resynchronize everything to the current (about 84" worth, and make sure they all show 100% no warning or "unable to...") state of the repositories. If you use the search command % pacman -Ss systemd you can see that even systemd is there. In artix (reference to one of the initial artix devs chris cromnix above) you don't see it because arch:core repository is not there. So ALL arch packages are "here".
4 If and when Manjaro fixes pamac for pacman 6, and artix people adopt their fix or fork their own, and when and if someone updates the AUR pamac package, you have to make sure that your user's services are correct. That means that dbus and consolekit are active (boot-user tree and user services), because pamac needs to run as both user and root and be able to upgrade and downgrade rights. You need root rights to update/sync pacman, to install and remove, you can search as user, you MUST be a user to build packages from AUR, you must be root to install them. As user if you type % pacman -Sy it fails, pacman -Ss pacman shows something. The gui for pamac is pamac-manager, pamac alone is just the cli wrapper for pacman and an aur helper.
Pacman doesn't have anything to do with AUR, what you do with aur has to be done away from pacman. If a correctly built package results then pacman can install it for you with pacman -U as said above.
5 What specifically is the problem with your pacman you have to help us understand so we can help you to fix it.
Provide the output:
% sudo pacman -Sy
% pacman -Ss alpm
% sudo pacman -S cower
6 Octopi is an AUR package/s pacman never showed octopi in its repositories. If some "other" distro on its own repositories, apart from Arch, had octopi or pamac that has nothing to do with arch or obarun or pacman.
Now, you want to have access to AUR packages, so give us the output of the above commands and we will go from there.
Also provide us with the output of this command.
% 66-intree -zg
Note, always, when you see % it indicates a user, # indicates root, which can be substituted with % sudo, so % sudo 66-intree -zg is the same as # 66-intree -zg. The z option is for color, we will not see it but you will :)