The script itself runs on Debian/Ubuntu/Archlinux x86-64. Follow the readme.
I am running an image created by his script daily, but it has been a while since I tested the script itself, should be okay.
You could give this a try, if you are interested in Archlinuxarm, or I could build an image already if you do not have a system to run the script.
It is mainline U-Boot, Collabora’s mainline linux kernel fork (a few months old, so no hdmi-rx)
Postinstall script installs standard Gnome, Mesa, Kodi and a patched ffmpeg (from LibreElec) for hardware decoding.
So no tweaks and no extensive tests done. You can use it to start with and tweak further, but this is not suitable if you just need a ready to go image with everything immediately functional 100%.