Do you already use esphome mqtt with autodiscovery turned on?
# Example Home Assistant configuration.yaml entry
mqtt:
broker: ...
discovery: true
This is the way I use my esphome-sensors with openhab. They are getting automatically discovered with all channels via the mqtt-binding.
(For autodiscovery to work, you have to install jsonpath-transformation and jinja-transformation, too. Like I described it here)