MQTT physical alarm panel

I’m going to build a home alarm system with door and motion sensors. The plan is to use MQTT and Node Red to configure the different states and triggers. Arming, motions, etc. What I need help with is to find a solution for guests like neighbors and others to access the home and disarm in a traditional way with a physical alarm panel. I don’t want it to feel to DIY Arduino like and a dedicated Android device feels overkill and cost too much. Any idea how to solve this in a cheap and reliable way? I was hoping to find a clean alarm panel that can send an arm and disarm MQTT message.

Many thanks

I am using this Android app on an very old mobile phone. Workshop very well since 2 years. And old android phones are very cheap. For most other solutions the housing alone was more expensive than an old phone.