How can I optimize SwiftUI CPU load on frequent updates

Although I know you'll again blame my naming conventions I decided to add a small example here: it does nothing except the peakmeter stuff and still causes a CPU load of 25% to 30% for 128 channels. This CPU load merely changes if you decrease the size of the window to only show two channels, while starting the example with only two channels (set s_NbPeakmeter = 2) shows a much lower cpu load. So invisible views also seem to cause CPU load?

import SwiftUI

class CPeakmeterManager: NSObject, ObservableObject
{
    static public let s_NbPeakmeter: Int = 128

    @Published var m_VecPeakmeterValues: [CGFloat] = []

    var m_Timer: Timer? = nil

    override init() 
    {
        super.init()
        
        m_VecPeakmeterValues = [CGFloat](repeating: 0.0, count: CPeakmeterManager.s_NbPeakmeter )
        
        m_Timer = Timer.scheduledTimer(timeInterval: 0.05, target: self, selector: #selector( OnTimer ), userInfo: nil, repeats: true)
    }
    
    @objc func OnTimer() 
    {
        for ChannelIndex in 0..<m_VecPeakmeterValues.count
        {
            m_VecPeakmeterValues[ ChannelIndex ] = CGFloat.random(in: 0...1)
        }
    }
}

struct PeakmeterView: View
{
    @Binding var b_PeakmeterValue: CGFloat

    var body: some View 
    {
        GeometryReader { geometry in
            ZStack(alignment: .trailing) {
                
                HStack(spacing: 0) {
                    Rectangle()
                        .frame( width: 0.4 * geometry.size.width, height: 10 )
                        .foregroundColor(.green)
                        
                    Rectangle()
                        .frame( width: 0.3 * geometry.size.width, height: 10 )
                        .foregroundColor(.yellow)
                            
                    Rectangle()
                        .frame( width: 0.3 * geometry.size.width, height: 10 )
                        .foregroundColor(.red)
                }

                Rectangle()
                    .frame(width: min( ( 1.0 - b_PeakmeterValue ) * geometry.size.width, geometry.size.width), height: 10)
                    .opacity(0.9)
                    .foregroundColor(.gray)
                }
        }
    }
}

@main
struct PeakmeterTestApp: App {

    @StateObject var m_PeakmeterManager = CPeakmeterManager()

    var body: some Scene {
        WindowGroup {
            ContentView().environmentObject(self.m_PeakmeterManager)
        }
    }
}

struct ContentView: View {

    @EnvironmentObject var m_PeakmeterManager: CPeakmeterManager

    var body: some View {
        ScrollViewReader { proxy in
            ScrollView {
                ForEach(0 ..< CPeakmeterManager.s_NbPeakmeter, id: \.self) { ChannelIndex in
                    PeakmeterView( b_PeakmeterValue: $m_PeakmeterManager.m_VecPeakmeterValues[ ChannelIndex ])
                        .frame(width: 150)
                }
            }
        }
        .padding([.top,.bottom],12)
    }
}