Help for buying a board for my project

The obvious option is to stay with the hardware you already have if you have no concrete reason for changing it.
For your application, I'd probably consider an ESP8266 which integrates with the Arduino IDE and is generally better specified. But (a) it is 3.3 volt and (b) it does not have so many usable pins, eg it has only one analog pin and (c) it is not so well documented.