Hi Brian! We are actively working on comprehensive documentation/examples that address this very topic.
@breezy-hamburger-69619 and
@creamy-potato-29402 can answer more questions about that.
We actually use Pulumi internally to run the SaaS, although we do keep a human in the loop to approve changes before running an update.
You might be interested in
https://github.com/pulumi/examples/tree/master/kubernetes-ts-staged-rollout-with-prometheus which shows one way you could use Pulumi to do gated CD with Prometheus in the loop. We'd be happy to answer any questions!