SwiftUI Preview Canvas doesn't load Decoded Struct data from local file

Question

I'm trying to get SwiftUI Previews working (with already downloaded API data) so that I don't need to run the app in simulator. Not sure what is wrong/how to go about it.

I've seen a few YouTube and (a lot) of SO on how to get this done but still hitting a wall. Appreciate pointers. (Note: 1st time trying to learn SwiftUI by porting a view of my app)

The data is going to be read-only, so there's no use for @State or @Bindings I believe and shouldn't be part of the @EnvironmentObject as well?

The YouTube's I've seen and google links are mainly using (locally stored) JSON files and they work.

eg: https://www.youtube.com/watch?v=hfjZNwayXfg and https://www.youtube.com/watch?v=EycwLxTU-EA

@available(iOS 13, *)
struct avatarView: View {
  let weeklySummary: [HelperIntervalsIcu.icuWeeklyData]
  
  func getAvatarPic() -> UIImage? {
      if let avatarUrl = weeklySummary.last?.icuAvatar {
        let avatarPicName = URL(fileURLWithPath: avatarUrl).lastPathComponent
        let avatarPicImage = HelperIntervalsIcu.loadAvatarPic(fileName: avatarPicName)
        return avatarPicImage
      }
    return nil
  }
  
  func getUserName() -> String {
    if let userName = weeklySummary.last?.icuName {
      return userName.prefix(1).capitalized + userName.dropFirst()
    }
    return "User Name Placeholder"
  }
  
  var body: some View {
    HStack {

      if let image = getAvatarPic() {
        Image(uiImage: image)
      } else {
        Image("profile-200x200")
      }
      Text(getUserName())
      Spacer()
    }
    
  }
}

@available(iOS 13.0, *)
struct IntervalsWeeklyView_Previews: PreviewProvider {
    static var previews: some View {
      let weeklySummary = HelperIntervalsIcu.loadWeeklySummaryFromFile()
      avatarView(weeklySummary: weeklySummary)
     
    }
}

The Preview just shows this

But when running in the simulator, it will work.

The data within HelperIntervalsIcu.icuWeeklyData is from a struct

  struct icuWeeklyData : Codable {
    var icuName : String
    var icuAvatar : String
  }