We use the lock 500i (TBL5iCPS) model. Built in VPN that is plug and play. There are good videos on YouTube demonstrating how it works.
We have their Virtual Central Lock that resides on our server and then we connect the locks that are in various regions to it over generic 4G cellular. This setup allows that always on VPN connection for Ignition to receive/request data.
I’d recommended inquiring for info through TosiBox so they can set you up with the right team/Vendors for best support and pricing.