Swift MapKit Multiple Polylines with different colors

I am trying to have different colors for each Polyline in MapKit in Swift. Here is a simplified example.

func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        if let overlay_ = overlay as? MKPolyline {
            let renderer = MKPolylineRenderer(overlay: overlay)
            if overlay_.title == "2" {
                renderer.strokeColor = UIColor.red
            } else {
                renderer.strokeColor = UIColor.blue
            }
            renderer.lineWidth = 5
            return renderer
        } else {
            return MKOverlayRenderer()
        }
    }

I have multiple polylines in a map where I set different overlay.title to differentiate between the colors.

Unfortunately it always take the last set color and applies it to all polylines.

In my example below I have 3 polylines with title: "0", "1" and "2". The result is red stroke color for all polylines.

Does anyone has an idea how to fix this? Do you need more code?

Code to add title:

  func showAllRoutes(map: MKMapView, route: Routes) {
    var coordinates: [CLLocationCoordinate2D] = []
    
    
    if dm.show_all_routes {
        for x in route.routes.indices {
            for y in route.routes[x].route_numbers {
                coordinates.append(CLLocationCoordinate2D(latitude: dm.alle_staende.locations[y].latitude, longitude:dm.alle_staende.locations[y].longitude))
            }
            
            let overlay = MKPolyline(coordinates: coordinates, count: coordinates.count)
            overlay.subtitle = "Route"
            overlay.title = "\(x)"
            
            map.addOverlay(overlay)
            
        }
        
    }
}

Got it. The problem is:

var coordinates: [CLLocationCoordinate2D] = []

It was placed wrong, it adds all lines and then they are basically the same. That's why they have the same color

 func showAllRoutes(map: MKMapView, route: Routes) {
    
    
    if dm.show_all_routes {
        for x in route.routes.indices {

            var coordinates: [CLLocationCoordinate2D] = []

            for y in route.routes[x].route_numbers {
                coordinates.append(CLLocationCoordinate2D(latitude: dm.alle_staende.locations[y].latitude, longitude:dm.alle_staende.locations[y].longitude))
            }
            
            let overlay = MKPolyline(coordinates: coordinates, count: coordinates.count)
            overlay.subtitle = "Route"
            overlay.title = "\(x)"
            
            map.addOverlay(overlay)
            
        }
        
    }
}