Tried various routes. Currently using bash scripts straight against the proxmox host. So lots of this

pct exec $CTID -- sh -c "mkdir test"

I've got a script that makes an arch lxc and turns it into a template.

And then bash scripts that deploys it with whatever custom stuff is needed (volume mounts, podman, files pushed into container etc).

Also a pacoloco server (arch/pacman cache) so that all the building and updating for everything is fast & not hitting the upstreams unnecessarily.

Terraform or Ansible also works for this but decided bash is ultimately less moving parts