I mean HA is open source, you are not going to beat that with your own code
I do want to look into that... still need hardware to interface with it either way, that's the part I'm testing and then basic software to talk to it. The RPI is just an end point for physical controls/sensors but idea is to offload the logic to a central place, which might be HA. Frigate NVR can interface with HA too so I eventually want to play with that.
Also not doing wifi, only POE wired. I don't really want anything home automation or surveillance related on wifi. Need power for the devices anyway so doing POE just makes sense. Eventually want to do ethernet with AVR, STM32, ESP32 or other micro, the RPI is just a way to quickly get me by. I already have all the chips needed to do ethernet and POE and interface with a MCU I just need to start breadboarding and experiment with it. End goal is to actually mass produce these devices and sell them. There is not really much on the market that I've found for open source wired home automation stuff that is not cloud based and does not require an app. My setup will be kinda niche as the type of people that buy the app based stuff probably don't care about planned obsolescence, open source or privacy nor do they want to run wire, but I'm sure there will be a small market for it. Will be cheap to produce once I have the design done anyway. The devices will be 100% standalone requiring no apps or anything, only thing they'll really require is open source software to interface with it, but the protocol will be fully open source. Could look at writing a HA integration for it too.