Tembo founder here - we're working on a "private data plane" feature, which relies on our open-sourced k8s-based data plane https://github.com/tembo-io/tembo-stacks - once we have that in place, this provider will hit our API, and will be able to deploy Postgres instances in your private k8s clusters.

We're also working on a CLI for local dev (that doesn't rely on Terraform), that will provide a simple code-based method to managing extensions in config files (among other things. Then you can run everything locally via `tembo instance start` or run remotely via `tembo deploy`.