On a similar note, I have some Daikin AC units, expensive ones and of course they didn’t come with wifi module which Daikin prices at 100+ Euro per module. After some searching around I found the Faikin [1] project and got one module to test for around 30 Euro and it works brilliantly for 1/3 of the price and provides even more functionality from what I’ve read with seamless HA integration.
If you just want to be able to control the ACs remotely, without remote sensing, you can buy some cheap IoT IR blasters (around $15–30 for Zigbee or WiFi versions). They'll often have control schemes you can download for your specific equipment (cloning the IR remote control that came with the AC).
Take a look at Sensibo. I have one and I'm pretty happy about it.