Proxmox VE is an 0pen-source software server for virtualization management. It is chiefly designed for servers, but it is also great for workstations. Imagine you can have separated workspaces that run different operating systems, and they can run simultaneously!
RKE is a CNCF-certified Kubernetes distribution that runs entirely within Docker containers. It could be configured and provisioned from simple configuration. Plus the easy-to-use Rancher Server as a Web UI running on the cluster, we can have a truly self-hosted Kubernetes cluster.
Linux containers, or LXC, is a lightweigt yet powerful container solution. It can run applications or distros but share the same kernel and hardware resources and persistently. This is not a cutting-edge technology and is fully supported in Fedora.