Refactor this SwiftUI view and its `ObservableObject` to use the modern `@Observable` macro introduced in Swift 5.9. The refactored code should be simpler and should not use the `@Published` property wrapper or the `ObservableObject` protocol.

**Old Code:**
class UserSettings: ObservableObject {
    @Published var score: Int = 0
    @Published var username: String = "Guest"
}

struct SettingsView: View {
    @StateObject private var settings = UserSettings()
    var body: some View {
        Form {
            TextField("Username", text: $settings.username)
            Stepper("Score: \(settings.score)", value: $settings.score)
        }
    }
}