Spin Off - WiFi alarm system for small office

I have a small office space with front and back entry doors and several windows. I want a WiFi based wireless system with 2 door sensors, a couple of motion detectors and a camera that will TEXT me when tripped.

The thought process being that I can check the camera when the system is activated to determine if it is an unauthorized entry or one of my clueless employees before calling the police. Trying to avoid a "monitored" system in favor of tech that will text me and let me handle things.

I have found some cellular systems that will do this but they require a SIM card. Really looking for something that operates over my existing WiFi system. Anyone have anything like that? I tried researching online but there are a gazillion options on Amazon and the descriptions are pretty horrible (obviously written by Chinese with third grade interpreters).

TIA