is there a way to delete external layout at any point ?

when the player is in collision with something … delete external layout “whatever”
i know there is a create event for it … but is there a delete event for external layouts in gd 5 ?

Once you create objects from an external layout in a scene, all objects in the layout become part of your scene just like any other objects. So you can not delete a specific layout only create the objects from a layout.
You need to delete the objects from the layout just like any other objects in the scene.