iOS14 Widget update every midnight

I'm making a widget app that shows today's date and calendar.

I want the widget refresh every midnight, so I tried several methods.
But eventually I failed to figure out how to do it.


First try : give entries that update every midnight. But it doesn't update the widget every midnight exactly.

Code Block 
struct Provider: TimelineProvider {
  func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> Void) {
    var entries: [SomeEntry] = []
    let currentDate = Date()
    let currentEntry = SomeEntry(date: currentDate), content: content)
    entries.append(currentEntry)
    for offset in 1 ..< 5 {
      let day = Calendar.autoupdatingCurrent.date(byAdding: .day, value: offset, to: currentDate)!
      let midnight = Calendar.autoupdatingCurrent.startOfDay(for: day)
      let entry = SomeEntry(date: midnight, content: content)
      entries.append(entry)
    }
    completion(entries, .atEnd)
  }
}

Second try : Dynamic Dates
I tried to use dynamic dates which was described here (https://developer.apple.com/documentation/widgetkit/displaying-dynamic-dates)
But it's not customizable, so I think I can't use it when making calendar widget.


Third try : Local notification
I tried to use local notification to reload widget every midnight.
But I found in iOS, I can't use silent local notification.


Fourth try : Background Tasks
I tried background tasks, but it won't refresh widget if the app is terminated.


I know that other popular widget app's widget updates exact every midnight. Even if I manually change device time, they work.

I think there is a way that can alert widget extension when date changes.

Any idea how to do it??