Access Screen Time total usage from main app when using DeviceActivityReportExtension

I am building a simple iOS app that shows the total phone usage time for today using the Screen Time APIs.

Architecture:

Main app → requests authorization using AuthorizationCenter.shared.requestAuthorization(for: .individual) → displays a DeviceActivityReport

Report extension → DeviceActivityReportExtension → calculates total usage using DeviceActivityResults<DeviceActivityData> → shows the number in a SwiftUI view

The report works correctly. The extension successfully calculates the total usage and displays it on screen.

Example logic inside the report extension:

for await activityData in data {
    for await segment in activityData.activitySegments {
        totalSeconds += segment.totalActivityDuration
    }
}

let totalMinutes = Int(totalSeconds / 60)

The problem:

I need the main app to access that number so I can store it daily in my own database.

I tried to send the value from the extension to the main app using:

• App Group + UserDefaults(suiteName:)
• App Group + shared file (FileManager.containerURL)
• writing inside makeConfiguration(...)

Example:

if let defaults = UserDefaults(suiteName: "group.myapp") {
    defaults.set(value, forKey: "savedTotalActivity")
}

But the main app cannot read the value. The report extension displays the number correctly, but the data never appears in shared storage.

Questions:

1. Is DeviceActivityReportExtension intentionally sandboxed so Screen Time data cannot be exported to the containing app?
2. Is there any supported way for the main app to access the total usage value calculated in the report extension?
3. If exporting the value is restricted, what is the recommended architecture for apps that want to store daily Screen Time totals for later analysis?

Goal:

I want a simple app that records something like:

2026-03-08 → 244 minutes
2026-03-09 → 198 minutes

and stores it inside the app database.

Any guidance on the correct architecture would help.