I have not mentioned Headscale before, even though I use it every day. I have my iPhone (on demand), my Mac, my Linux laptop (on demand), and my two VPS connected to it. Headscale is an open source, self-hosted implementation of the Tailscale control server. You can use the Tailscale client—which is available for all platforms—to connect to it. It is amazing, and worthy—at the very minimum—of a star on its GitHub repository.