Grub is and has been problematic for Manjaro. Everytime an other system in the same machine upgrades kernels or grub itself, it generates a /boot/grub/grub.cfg that is incompatible with Manjaro. Then Manjaro will not boot unless you have saved a stub of it menuentry from its own grub.cfg and patch it in the other systems. Then you can start Manjaro do a # sudo grub-install /dev/sd* and then # sudo update-grub to fix things.
You can uninstall grub from all other systems, but then what happens if Manjaro fails?
So, artix is just another system for Manjaro. Artix will create a boot grub entry that throws Manjaro into the known and familiar kernel panic, where you pull the plug and restart.
Someone at that “other forum” said it was about the intel-microcode that is included into the Manjaro kernel (which I didn’t know). No wonder you only find it in AUR! Because it is already within the system and this is why Manjaro’s graphics seem so good for anyone having intel only hardware.