You can run k3s with a single node. In that case it uses sqlite instead of etcd which is great for a smaller resource footprint. If you're comparing k8s distros, you'll be hard pressed to find a setup that uses fewer system resources.
Is it actually smaller though? For those non etcd data stores, Kine is often the component doing an etcd to database translation. Im my experience using it generated a load that was greater than a one node etcd instance.