It is possible to control it directly and with more control than any of the commercial offerings if you’re willing to get your hands a little dirty. Unlike IR control, you can read the status of all of the settings as well as change them. You can also set an external temperature if you want to use your own sensors to provide a better reading over larger spaces. (I have mine set up to use temp and occupancy sensors to do a weighted average based on occupancy in the living room/loft space of one of mine).
You can wire up an ESP8266 (such as a Wemos D1 Mini or similar) to each head unit to get control over wifi via MQTT.
It requires a custom connector to wire up, but it’s a relatively simple job. You’ll spend about $4-7 per head unit you want to integrate on parts (which beats the $150+ you’ll spend per unit for official offerings). Keep in mind, you’re wiring up to the same connector that these things use, but if you do it wrong, you’ll likely burn out the ESP8266 and could even damage your heat pump. That said, these are also smaller than the commercial wifi unit that hooks on the outside. Mine are completely hidden with no wires.
I did this on mine with no problems a few months ago and I couldn’t be happier. If your unit supports “wide vane” mode (oscillating left and right), that’s not available through the default HA climate panel. You can modify the climate panel to support it, it’s a bit of work to plumb through. You can also just make an input selector that sends mqtt commands which is really easy.
Thanks to these guys, there’s code and documentation of their reverse engineering of the protocol, as well as a custom component for HA :