Hey, it's William from Google here. You're right about the costs, I just wanted to point out that Autopilot does include one cluster in GKE's free tier. So you'll only pay the ~$73/month if you have more than 1 cluster.

There's (almost) no limit to what you can run in one cluster too, and Kubernetes namespaces can help to separate different environments to allow for sharing.

Cloud Run sounds like the perfect solution for your workloads though!