Proof of concept of using a SwiftUI `ImageRenderer` with a map, and how it blanks out the map.

ImageRendererPoC.swift

import SwiftUI
import MapKit

struct ContentView: View {
  
  @State private var mapRegion = MKCoordinateRegion(
    center: CLLocationCoordinate2D(
      latitude: 51.5, 
      longitude: -0.12
    ), 
    span: MKCoordinateSpan(
      latitudeDelta: 0.2, 
      longitudeDelta: 0.2
    )
  )
  
  @ViewBuilder
  var map: some View {
    ZStack {
      Map(coordinateRegion: $mapRegion)
      Text("Hello world")
        .font(.title)
        .bold()
        .padding()
        .background(Color.red)
    }
    .frame(width: 350, height: 300)
  }
    var body: some View {
      VStack {
        map
        Button(action: {
          let renderer = ImageRenderer(content: map)
          if let image = renderer.cgImage {
            
            // Set a breakpoint here and inspect the image that's produced.
            // The map will be replaced with a 'no entry' sign 🚫.
            print(image)
          }
        }) {
          Text("Create image")
        }
      }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}