UniFi Site-to-Site VPN Setup

I need a rock-solid, site-to-site tunnel linking two locations that already run on UniFi gateway controllers. Rather than relying on Site Magic or Teleport, I want the link established with OpenVPN so both LANs can talk to each other seamlessly.

Both controllers are up and reachable; I simply need help creating the tunnel, applying the right firewall rules, and verifying that devices on each subnet can ping and share resources across the link. Once the tunnel is live, I also want a brief record of the steps taken so I can maintain the configuration in the future.

Deliverables
• Fully operational OpenVPN site-to-site connection between the two UniFi gateways
• Any necessary firewall or routing adjustments implemented and documented
• Short handover guide (commands, screenshots, or export) for future reference

I’m looking to wrap this up ASAP, so please indicate your availability for a remote session and any prerequisites you’ll need from me.