Select All Outer or Exposed Faces Feature

Sometimes we have a 3rd party mesh that is messy on the inside like having alot of internal faces that are not visible from the outside, but we may have a water-tight outer part of the mesh. I think it is important that we have a feature that can select all outer faces that are essentially exposed to the outer world. Which can be used to invert the selection and thus select everything not visible and be able to delete it. An example mesh I have attached in this thread where there is no way to select all the outer faces blender.stackexchange.com/questions/282161/how-do-you-select-only-outer-faces-that-are-exposed-to-light

Notice that in the thread's attached blend file you cannot use the "select linked faces" L feature to do this type of aforementioned selection. We need a select ALL outside faces but NOT even the manual method of box selection tool can do the job although selection using the Vertex selection tool works as a workaround but that's tedious so we definitely need the select ALL method.