Recommendation for small VPN router with port security

Hello, I'm trying to set up a tunnel between a remote device that is not capable of VPN to the main office. I need the remote side (router/firewall) to have built-in port security (MAC filtering). I tried the RV160 from Cisco but it only has 802.1x which would require a RADIUS server on the remote end. I really only need 1 LAN port. The remote end also would have a dynamic IP and be behind a firewall.

The concern is that if the remote termination device (router/firewall) is stolen or lost, no one can just plug it in anywhere and have a connection back to the main office until something can be done to cut access.