I can't find any explanation on: install Artix as the next OS installation
After striving very hard to learn boot technique finally I have strongly believe it is about the separation of boot for efi and the internal boot component of Artix itself; this is what i clearly find in the result of MX linux installation utilizing grub2 (perfectly finished job of dual boot installation side by side Windows). It has separate efi ie. ESP which is named/mounted as /boot/efi while keeping MX stuffs itself in /boot of the same / root partition

How exactly to do it the definitive way ?

It's not quite clear to me what you want to achieve. Install Artix? Use the installation guide.