Teach me how to programmatically access IOT devices over LAN | Tasmota/ Home Asistant / Raspbery PI/

Hi Guys,
I'm building an indoor grow room for plants. I have to control the environment inside it (Air exchange, Temperature, Humidity) I want to do all this automation from a desktop computer over custom application developed specifically for this purpose.

So, as for start I spent good few weeks learning how to access Tuya devices programmatically over Tuya Cloud (using their cloud API)
I have learned a lot but realized that going over cloud is not reliable for my setup and concluded that controlling these devices MUST go over LAN without hitting any clouds!

After googling around I found that most common way to do that is to flash my IOT devices with Tasmota which would allow to control them over LAN,
So the requirement of this project is to provide a basic guide and working sample on how to flash and control just 1 device, so I have basic understanding and I'm able to develop the project further on.

Alternatively If you are familiar with any other method of controlling smart devices over LAN please let me know I'm open for that. Also if you have good skills in this area I would be very interested to work with you further on untill we complete entire project.

Devices I need to control:
- Smart Humidity/Temperature sensor.
- Smart electricity sockets.
- Smart Infra Red controller (for Air Conditioner)