I too am stunned about this basic operation. I am replacing an alarm whose control head died that is 8 years old and it had different sounds for alarms and notifications.
As someone else stated “It is not ready for prime time with issues like this”.
I just bought it and was very surprised and might not keep it because of this.
Here is the only workaround I could come up with, and it is not ideal.
There is one sound app on Google play called “Notificon” by Gautham S Yaji
It will allow you to select voice or custom sound notifications in an Android app.
All other apps that I found that were around a few years ago are no longer supported.
I downloaded a MP3 file from Soundbible.com called Siren Noise, but it could be any of their siren selections.
I copied the file to internal storage/notifications so it will appear on the notification sound list
I used the app “Notificon” and selected the Ring app and then selected the siren sound.
The volume must be set in the general settings of the Notificon app, it uses its own volume setting.
Now I get a siren when an alarm occurs at whatever volume I set the Notificon app to use.
I had to turn off entry delay and mode updates and event updates in the Ring app or I get an alarm entering or leaving. I turned off alerts on all of the individual sensors.
Basically any notice for which you don’t want a siren sounding you must turn off
This is not ideal, because I used to like getting a simple push notification on my old alarm when it was armed or disarmed.
The sound it used was the default sound setting on an arm or disarm but a siren on an actual alarm, the way it should be.
They desperately need to fix this. A burglar alarm should sound like a burglar alarm not a ding.