This will set up a Raspberry Pi to connect to a Tesla Powerwall Gateway (TEG) and bridge that connection to the ethernet connected LAN.
As of Tesla Powerwall Firmware 25.10.1, a local host based static route using the Powerwall LAN IP (ie. sudo ip route add 192.168.91.1 via $POWERWALL_IP) is no longer supported by the Powerwall. Tesla is blocking access via this method. You will need to use a bridge method (as shown below) or have your host direclty connect to the WiFi Access Point on your Powerwall (gateway) to get the extended metrics (vitals).
Below is a method to set up a Raspberry Pi to be a bridge between your LAN and the Powerwall, which will require you to set up a local host baed route (ie. sudo ip route add 192.168.91.1 via $RPI_IP). Alternatively, you can see a method to host pypowerwall on Raspberry Pi that connects to both your LAN and Powerwall. That is described here: https://github.com/jasonacox/Powerwal