I have a Raspberry on POE (with UPS for router, 4G backup connection, switches, WiFi and POE devices) and my alarm related devices are Z-Wave battery-only or in case of the Aeontec siren as mains-powered with battery backup. - During a couple of power outages over the years, this has been reliable.
I see Aoentec has announced a new version 6 of their siren, and in the meantime I will look into exposing the configuration parameters for sound type and volume for the Aoentec Siren Gen5 as channels, to get the items I am looking for. - Alternatively I can change the configuration via rules and HTTP requests to the API. Then I can use the existing sirens for different scenarios with clear audio difference to recognize the alarm type.