Help needed! Load bearing wall? Any advice on this?

I have this wall on the ground floor with another level on top. There is no wall above it on the top floor.

I want to know if any of you out there can tell me more about this wall, if it is possible to remove it all (fully about 18' or even partially) or should I just not touch it at all?

I will be bringing a structural engineer to comment too but thought I would ask here in case any generous folks could shed light on this and reduce my anxiety.

Any help/advice is appreciated!

Pictures in comment.