I need to use and copy Artix-dark theme to another Arch OS i.e. Manjaro, is there a way to copy the package Artix-dark to another systemd Arch ?
I have nver done this but I would look at artix related packages such as (but not limited):
artix-backgrounds
artix-branding-base
artix-dark-theme
artix-desktop-presets
artix-grub-theme
artix-icons
artix-gtk-presets
artix-*-presets
Yes, there is, read this wiki article (https://wiki.artixlinux.org/Main/Troubleshooting#When_I_switch_theme_in_Plasma.2FMATE.2FXFCE.2FAnyDEorWM_the_colours_are_broken.21) to understand how. Existing user accounts will have to copy over settings from /etc/skel, though, or the theme won't be consistent - why is explained in the linked article.