Arduino, triple temperature measurement, small App

First, I’m a technician with no experience of programming an Arduino or whatsoever. So I can’t help in programming and give only technical information and needs. Measuring on a cooling unit at a sample rate of 1 measurement/minute (saving battery), 3 NTC (preferable) temperature probes and 2 reed contacts. At a plant, there can be 20 to 30 Arduino’s fulfilling same task. As soon as some control parameters are triggered, an alarm (contact) is generated and a led starts flashing on the housing and additional a sound alarm as well. Sound can be switched off by a push button and reactivates after a certain time if alarm still exists. Preferable battery controlled. Arduino monitors state of the battery and alerts when battery drops below safe level. Optionally, preferable via Zigbee (or similar but better than Bluetooth), alarm contacts are sent to a main controller, controlling all the different Arduino’s. This main controller generates an alarm sending a general alarm to a mobile phone (Wifi) via a small app, specifying which Arduino activated. I must be able to control the Arduino ‘decision’ software so that I can adapt easily on-site the triggering values. Temperature values needs to be compared to each other and triggered after certain elapsed safety time. If we could follow in real-time the measured values (app on phone) while programming the Arduino, that would be great. Specify where you think additional PCB’s needs to be added to a standard Arduino (or clone) I need to have an idea for the small Arduino board and additional the main controller.I can see where the automated messages are cooming from Several bidders pointed me to the fact that a ESP32 would be a better solution for this project. It's indeed a better solution=. Perhaps those not familiar with this board can retract thier bid