<TelerikMap @ref="MapRef">
  <MapLayers>
    <MapLayer Type="@MapLayersType.Marker" Data=@MyData" @ref="LayerRef" />
  </MapLayers>
</TeleriKMap>

@code {
  TelerikMap MapRef {get; set; }
  TelerikMapLayer LayerRef { get; set; }

  MyData = new List<MapMarker>() {
    // Data in here
  };

  private void WholeComponentRefresh() {
    MapRef.Refresh(); // Existing functionality
  }

  private void AddMarker() {
    MyData.Add(new MapMarker()); // Map ignores this because it does not treat as observable
  }

  private void MyLayerRefresh() {
    LayerRef.Refresh(); // If we don't have observable, could we at least get per-layer Refresh?
  }
}