public void RemoveLayer( 
   Layer layer
)

var map = MapView.Active.Map;
if (map == null)
  return;
//Get the group layers first
IReadOnlyList<GroupLayer> groupLayers = map.Layers.OfType<GroupLayer>().ToList();
//Iterate and remove the layers within the group layers that are unchecked.
foreach (var groupLayer in groupLayers)
{
  //Get layers that not visible within the group
  var layers = groupLayer.Layers.Where(l => l.IsVisible == false).ToList();
  //Remove all the layers that are not visible within the group
  await QueuedTask.Run(() => map.RemoveLayers(layers));
}

//Group Layers that are empty and are unchecked
foreach (var group in groupLayers)
{
  if (group.Layers.Count == 0 && group.IsVisible == false) //No layers in the group
  {
    //remove the group
    await QueuedTask.Run(() => map.RemoveLayer(group));
  }
}

//Get Layers that are NOT Group layers and are unchecked
var notAGroupAndUnCheckedLayers = map.Layers.Where(l => !(l is GroupLayer) && l.IsVisible == false).ToList();
//Remove all the non group layers that are not visible
await QueuedTask.Run(() => map.RemoveLayers(notAGroupAndUnCheckedLayers));

var map = MapView.Active.Map;
if (map == null)
  return;
//Get the group layers
IReadOnlyList<GroupLayer> groupLayers = map.Layers.OfType<GroupLayer>().ToList();
foreach (var group in groupLayers)
{
  if (group.Layers.Count == 0) //No layers in the group
  {
    //remove the group
    await QueuedTask.Run(() => map.RemoveLayer(group));
  }
}