NEHotspotNetwork.fetchCurrent provides an object with always 0 signalStrength

I have this code:

import SwiftUI
import NetworkExtension
import CoreLocation

class WifiDataViewModel: NSObject, ObservableObject, CLLocationManagerDelegate {
    @Published var ssid: String = ""
    @Published var signalStrength: Double = 0
    
    private let locationManager = CLLocationManager()
    
    override init() {
        super.init()
        locationManager.delegate = self
        locationManager.requestWhenInUseAuthorization()
    }
    
    func fetchWifiData() {
        NEHotspotNetwork.fetchCurrent { network in
            guard let network else {
                print("No available network")
                return
            }
            self.ssid = network.ssid
            self.signalStrength = network.signalStrength
        }
    }
    
    // CLLocationManagerDelegate methods
    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        if status == .authorizedWhenInUse || status == .authorizedAlways {
            fetchWifiData()
        }
    }
}

struct ContentView: View {
    @StateObject private var viewModel = WifiDataViewModel()
    
    var body: some View {
        VStack {
            Text("Wi-Fi Data")
                .font(.title)
                .padding()
            
            Text("Network SSID: \(viewModel.ssid)")
                .font(.subheadline)
            
            Text("Signal Strength: \(viewModel.signalStrength) dBm")
                .font(.subheadline)
            
            Button(action: {
                viewModel.fetchWifiData()
            }) {
                Text("Fetch Wi-Fi Data")
                    .font(.headline)
                    .padding()
                    .background(Color.blue)
                    .foregroundColor(.white)
                    .cornerRadius(10)
            }
        }
        .padding()
    }
}

The goal of this app is to find a weak spot in my home network, to manage router placement better.

I want to get wifi signal strength in any possible way, either it will be rssi value or [0, 1] value.

Documentation tells that signalStrength should provide such value, but it isn't. https://developer.apple.com/documentation/networkextension/nehotspotnetwork/1618923-signalstrength

From additional setup, Access Wi-Fi Information capability is granted.

iOS 16.4, Swift

please help me resolving this issue