It is possible to setup a LAN to LAN VPN connection between two Unraid systems running Wireguard. The steps below should work on simple networks, if yours is more complicated then you'll need to figure out how to adapt it. This assumes you already have at least one working WireGuard connection and are familiar with how it works.
First, gather the following information for your two networks. The names and numbers below are samples, you'll need to adjust for your situation: