I never said it wasn't a good idea. Almost 6 months later it serves me perfectly well. There was no original app. The AC itself was here when I moved in, it's an obscure manufacturer no one has ever heard about and I recon it's been here since the building was built around 2007. All I could find out about it was that it was made in South Africa and that's it. Infrared communication is incredibly simple on those devices and it's a matter of two hours to reverse engineer them(no shifting, rotations or any of that fancy stuff). All in all it cost me around 20 bucks and ~day to get it to work+the crazy stupid ui running off an actix webserver. But if I had the option to buy a remote control which works with it, I would have gladly done that instead(tried several universal remotes, none of which worked).
My point was that this does solve my problem but it's an incredibly niche problem for an even smaller niche market. The owners of this AC from the same unknown manufacturer, that either can't find a spare remote or want to make it wifi enabled. It's insanely specific, isn't it? Let's not fool ourselves, writing the software is the easy part and fairly inexpensive when you can do it yourself, get a cheap stm32 board and flash it. Manufacturing on the other hand is a whole different ball game and honestly I can't justify the work of developing, manufacturing, distributing and dealing with taxes at the end of each month, all for 300 bucks tops(I'm probably far too optimistic).
edit: esp32, not stm32(I'm mostly playing with stm32 lately).