CustomSliderContentView.swift

import SwiftUI

@available(iOS 16.0, *)
struct ContentView: View {
  @State var sliderValue = Double(0)
  var body: some View {
    VStack {
      Text(String(sliderValue))
      Slider(value: $sliderValue, in: 0...100)
      CustomSlider(value: $sliderValue, in: 0...100)
    }
  }
}

struct CustomSlider: View {
  @Binding var value: Double
  let bounds: ClosedRange<Double>
  
  internal init(value: Binding<Double>,
                in bounds: ClosedRange<Double>) {
    self._value = value
    self.bounds = bounds
  }
  
  var body: some View {
    ZStack {
      ProgressView(value: value / bounds.upperBound)
        .padding(.horizontal, 1)
      SliderThumbView(value: $value, bounds: bounds)
    }
  }
}