Yep - we expose the Kubernetes API (and add mutating controllers to help automate some of its actions).
Right now we don't do "hosted control plane", rather - you can either use our hosted clusters where you have namespace-level access (so you still get to use Kubernetes, just not all of the resources, for example, no `Nodes`), or you can attach your own cluster to our UI (with the advantage that we can setup ingress and forward traffic to you, which is perfect for a home-hosting setup).
Hosted control plane is something im watching closely though - I'd really love to offer that as a service, but since we're small, we're trying to focus hard on a core offering. Will be considered in the future though!
I'm interested in/have previously given up on a product where the control plane is managed for me, I can join the cluster with bare metal nodes, and then it's just Kubernetes.