“The next Arch install, I’ll document the setup” - Famous last words! :-)
Seriously, I wonder how good my approach would work with a rolling distribution like Arch. I would be afraid, that pacman updates would drift/change the system and over time the delta to my assumed setup grows… OTOH if you keep your scripts in sync with Archs updates, you might simply distribute the maintenance of your Ansible script. If you go full Ansible with Arch, please give an experience report in 6 months!