How to detect always-on display in Swiftui?

According to apple

On devices that include an Always-On display, the system dims the screen to preserve battery life and renders Live Activities on the Lock Screen as if in Dark Mode. Use SwiftUI’s isLuminanceReduced environment value to detect reduced luminance on devices with an Always-On display and use images that look great for reduced luminance.

But it seems to have no effect in live activities when displayed in the lock screen with AOD

  @Environment(\.isLuminanceReduced) var isLuminanceReduced
    Image("background1")
                            .resizable()
                            .aspectRatio(contentMode: .fit)
                            .frame(height: 400)
                            .offset(y:-40)
                            .brightness(isLuminanceReduced ? -0.5 : 0)