Ruby web applications have a history of absurdly high resource usage and failure stories compared with something like Go. If the selling point of this is for individuals and small businesses to run this instead of AWS/GCP, it may not be any cheaper once you start running this control plane.
AWS/GCP is frequently 2x-3x as expensive as doing it yourself, depending on your usage patterns as some things are vastly more overpriced than others (e.g. egress), sometimes a bit lower, but if your control plane is more than a rounding error in your overall cost you're doing something very wrong.
