Recently I managed to implement the NEC protocol for my DeLonghi N90 and N81 air conditioners on a raspi. Using an ir transmitter it is possible to mimic the original remote control. The raspi itself will provide some MQTT topics for reading and setting the status of the air conditioners.
What you need is a spare raspi, an ir transmitter and of course the software: https://github.com/8cH9azbsFifZ/pac-n90-raspi.