ESP32/ESP8266 based solution for Bosch GreenTherm 9000

Looking for an ESP32/ESP8266 based solution to connect my Bosch GreenTherm 9000 series tankless gas water heater to HA. Even just monitoring usage stats would be helpful.

I’m aware there’s an OEM WiFi module (expensive and unavailable), so I’m hoping there’s something similar to Mitsubishi2MQTT or an ESPHome-based project that documents how to connect to the water heater.

I do know the OEM module is not EMS based, so I do think some bit of reverse engineering might be in order.

Happy to help test if anyone wants to take this on!

(Cross posted to projects; will remove there if necessary).