Hello! Yes, the S2S WiFi relay should work with your extended router setup. The WiFi relay is designed to connect to your existing WiFi network and extend its range. It should work seamlessly with your extended router, providing you with a stronger and more reliable WiFi signal in areas where your main router's signal may be weak.
If you haven't tried using the WiFi relay with your extended router yet, I recommend giving it a try. Follow the setup instructions provided with the WiFi relay to connect it to your network. Once connected, you should notice an improvement in WiFi coverage in your home or office.
If you encounter any issues during the setup process or have specific questions about using the WiFi relay with your extended router, feel free to ask for further assistance. Good luck, and I hope the WiFi relay helps improve your WiFi experience!