I have successfully managed to integrate my new VIVAX ACP-12CH35AEHI/I+ the dumb way via IR.
I spent $3($6 off sale) on an AliExpress IRC03 IR transmitter/receiver -
Flashed it with the IrRemoteESP variant of OpenBeken (requires soldering, standard variant does not support ACs for IR), and connected it to HA via MQTT.
Then I found out my AC uses Coolix commands by reading the OpenBeken IR logs in their webapp, so I used this article Controlling Coolix-compatible AC using OpenBeken/OpenBK7231T-Compatible IR Blaster | Octo’s rants and setup AppDaemon addon in HA.
After some edits, back and forth with the author of the script, and playing with MQTT Explorer to diagnose some issues, I had a working setup, here - scripts/coolix.py · master · Martin / configs · GitLab
The AC already comes with its own proprietary Wi-Fi module which I refuse to use, but nothing prevents one from setting that up to get info about AC state if someone else is controlling it through the actual remote.
This should be applicable to any AC that uses Coolix commands.
EDIT: It seems that my AC came with the EU-OSK105 Wi-Fi module, so integration should be possible for me via that too.