To note, the emonTx6 will work as a standalone device with the emonWiFi board or even directly connected to a suitable device by USB to read the serial data (e.g. using emonhub).
Whilst the emonWiFi will utilise ESPHome for its firmware, there is no requirement to have or use Home Assistant. The emonTx6/emonWiFi combo can communicate with any suitable HTTP or MQTT endpoint as well as Home Assistant. These endpoints can all be used simultaneously in any combination.