Thing is, nothing in Terraform works cross-provider - it's just a (often clunky, though it got better) DSL over JSON which makes for nicer way to call vendor APIs. But I need to know all the details of those APIs anyway.

With K8s, the basics that "just work" are pretty wide, the bits that are specific to vendor that are necessary are usually small and contained, and for everything else I have extensible API that allows abstractions like crossplane.io