I find that setting up any kind of VPN is always a PITA. I'm so relieved since I found sshuttle [1].
a simple dashboard to set up and manage a wireguard vpn server
They run something like Ethernet over IP, so your "segment" auto-configures via normal ARP, as if it were a LAN, as long as your devices have a connection. What's great e.g. for laptops and phones is that devices physically on the same network do talk directly, not via a VPN proxy node.