Stack feature not working as per plan.

What are: barHeight, barColor, progress, icon and duration?

Please format your code properly, as you have some code outside of the code block, making it impossible to figure out what your code should actually look like.

What is ProgressiveBar ? Is it

            RoundedRectangle(cornerRadius: 10)

What do you mean by above or on top. Please show what you get and what you want.

Why do you need geometry reader and not just set the zIndex of the progress bar ?

I edited your code to guess and complete missing parts:

struct ContentView: View {
    
    let barHeight: CGFloat = 30
    let barColor = Color.gray
    let duration: Double = 10
    let icon = "globe"
    @State private var progress = 0

    var body: some View {
        ZStack(alignment: .leading) {
            // Background bar RoundedRectangle(cornerRadius: 10)
            //    .fill(Color.gray.opacity(0.3))
            //     .frame(height: barHeight)
            
            // Set height to the specified barHeight
            // Progress bar
            GeometryReader { geometry in
                RoundedRectangle(cornerRadius: 10)
                    .fill(barColor)
                    .frame(width: CGFloat(progress) * geometry.size.width, height: barHeight)
                    .animation(.linear(duration: 10), value: progress)
            }
            .cornerRadius(10)
            
            // Icon and label
            HStack {
                Image(systemName: icon)
                    .foregroundColor(.black)
                    .font(.system(size: 28))  // Increased size
                    .padding(.leading, 8)
                    .onTapGesture {
                        progress = 10  // Added to see progress
                    }
               Spacer()
                Text(String/*timeString*/(format: "%.1f", /*from: */duration * Double(progress)))
                    .foregroundColor(.black)
                    .bold()
                    .font(.system(size: 24))  // Increased size
                    .padding(.trailing, 8)
            }
            .frame(width: UIScreen.main.bounds.width * 0.9, height: barHeight)
            .zIndex(1)  // Ensure the HStack is on top
        }
        .padding(.horizontal)
    }
}

The progressBar is above:

I changed ZStack to VStack and removing geometryReader and get this:

struct ContentView: View {
    
    let barHeight: CGFloat = 30
    let barColor = Color.gray
    let duration: Double = 10
    let icon = "globe"
    @State private var progress = 0

    var body: some View {
//        ZStack(alignment: .leading) {
        VStack {
            
            // Set height to the specified barHeight
            // Progress bar
//            GeometryReader { geometry in // REMOVED
            RoundedRectangle(cornerRadius: 10)
                .fill(barColor)
                .frame(width: CGFloat(progress) * UIScreen.main.bounds.width, height: barHeight) // WE CAN get screen width directly
            //  .frame(width: CGFloat(progress) * geometry.size.width, height: barHeight)
                .animation(.linear(duration: 10), value: progress)
            // }
                .cornerRadius(10)
            
            // Icon and label
            HStack {
                Image(systemName: icon)
                    .foregroundColor(.black)
                    .font(.system(size: 28))  // Increased size
                    .padding(.leading, 8)
                    .onTapGesture {
                        progress = 10  // Added to see progress
                    }
               Spacer()
                Text(String/*timeString*/(format: "%.1f", /*from: */duration * Double(progress)))
                    .foregroundColor(.black)
                    .bold()
                    .font(.system(size: 24))  // Increased size
                    .padding(.trailing, 8)
            }
            .frame(width: UIScreen.main.bounds.width * 0.9, height: barHeight)
            // .zIndex(1)  // Ensure the HStack is on top
            Spacer() // ADDED THIS
        }
        .padding(.horizontal)
    }
}

Is it what you are looking for ? If so, don't forget to close the thread by marking the answer as correct.

And now with progress bar overlaying:

struct ContentView: View {
    
    let barHeight: CGFloat = 30
    let barColor = Color.gray
    let duration: Double = 10
    let icon = "globe"
    @State private var progress: CGFloat = 0

    var body: some View {
        ZStack(alignment: .leading) {
//        VStack {
            // Background bar RoundedRectangle(cornerRadius: 10)
            //    .fill(Color.gray.opacity(0.3))
            //     .frame(height: barHeight)
            
            // Set height to the specified barHeight
            // Progress bar
//            GeometryReader { geometry in
            RoundedRectangle(cornerRadius: 10)
                .fill(barColor.opacity(0.5))    // To see through
                .frame(width: CGFloat(progress) * UIScreen.main.bounds.width, height: barHeight)
            //  .frame(width: CGFloat(progress) * geometry.size.width, height: barHeight)
                .animation(.linear(duration: 10), value: progress)
            // }
//                .cornerRadius(10) // That's redundant

            // Icon and label
            HStack {
                Rectangle() // to avoid frame moving when  animation starts)
                    .fill(.clear)
                    .frame(width: UIScreen.main.bounds.width * 0.05, height: barHeight)
                Image(systemName: icon)
                    .foregroundColor(.black)
                    .font(.system(size: 28))  // Increased size
                    .padding(.leading, 8)
                    .onTapGesture {
                        progress = 1  // Added to see progress
                    }
               Spacer()
                Text(String/*timeString*/(format: "%.1f", /*from: */duration * Double(progress)))
                    .foregroundColor(.black)
                    .bold()
                    .font(.system(size: 24))  // Increased size
                    .padding(.trailing, 8)
            }
            
            .frame(width: UIScreen.main.bounds.width/* * 0.9*/, height: barHeight) // Changed to avoid frame moving when  animation starts
            .zIndex(1)  // Ensure the HStack is on top
            
            Spacer() // ADDED THIS
        }
        .padding(.horizontal)
    }
}

We get this during progress:

May be we could use overlay, but did not try.