Hello,
With Eufy Security, as it is not possible to set on / off directly from homekit, may be it will be possible to use 3D Touch or Haptic Touch on the icon of the app.
May be with the implementation of shortcut in the app, it will be possible to arm security on / off with voice.
And, I think the best solution and the quickest is a widget with the modes in the lock screen.
Best regards
Laurent