Thanks @MrBlue,
I have no plans to support other security panels right now. Also, there is an app for Eufy already.
The integration between the Ring Keypad is based on the API in Heimdall and the realtime events Heimdall emits on Surveillance Mode changes.
Basically any devices’ app* can talk to the API and receive the events.
Maybe @martijnpoppen is willing looking into integrating the Eufy panel with Heimdall, Documentation can be found here: How to get access to API Endpoints from another app. · daneedk/com.uc.heimdall Wiki · GitHub
(* The app will need an API key provided by me)