Thanks for the post and the question:
https://developer.apple.com/documentation/alarmkit/alarmmanager/alarmconfiguration#overview
What happens when you change the sound file on the alert configuration?
let configuration = AlarmManager.AlarmConfiguration(countdownDuration: Alarm.CountdownDuration(preAlert: 10, postAlert: 10),
schedule: nil,
attributes: attributes,
secondaryIntent: repeatIntent,
alertConfiguration: AlertConfiguration(title: "Eggs are ready!", body: "Time to eat!", sound: .default))
Alert Sound:
https://developer.apple.com/documentation/ActivityKit/AlertConfiguration/AlertSound
https://developer.apple.com/documentation/activitykit/alertconfiguration/sound
AlarmKit Resources:
AlarmKit FAQ is always important:
https://developer.apple.com/forums/thread/797158
AlarmKit volume:
https://developer.apple.com/forums/thread/813519?answerId=873409022#873409022
AlarmKit API
https://developer.apple.com/documentation/AlarmKit
Albert Pascual
Worldwide Developer Relations.