I developed an app to manage sensors, actuators, cameras, and GPS. It's simple, easy to use —less powerful and flexible than others solutions like Home Assistant but maybe a better fit for your project.

The app's website is https://iot-assistant.github.io/.

I have developed Arduino libraries and examples to simplify devices development. Most of the examples use M5Stack devices. Documentation and code is available here

We have GPS unit we can integrate with Atom and M5Stick but we can not send the position data using mobile network. It would be great to have 3G or GSM hat stick or unit because usually WiFi networks are not availables for GPS applications (car tracker for instance).

Thanks and regards.