Wireguard is a VPN that comes built into Linux kernels >= 5.6 It also has clients for OSs like Windows, OSX, and Android.
If you're looking for how to have a virtual LAN party, Wireguard is a great way to do it. Since it's cross platform. You can even play Windows games on Linux using Lutris and network them with Wireguard to get Windows and Linux machines playing together.