This is really awesome, the host count there is impressive. For the smart proxies you mentioned having globally, do you use any parts from the documented load balancing method from Configuring Smart Proxies with a load balancer ? Or is it all custom?
Since you mentioned containers too, I’ll pass along RFC: Foreman Production Installation via Containers and Podman Quadlets just in case you haven’t seen it yet. The containerized installer project is called foremanctl now.