"Perfectly Splendid"
Like said, it's not completely a ghost story, but dwelling in the past and a will to relive the past is a ghost in itself.
Not very scary, but will suggest to watch it in a dark room all alone and your heart may skip a beat or two.
The one thing horror movies or TV series don't have is a good story, but The Haunting of Bly Manor has an incredible story weaved around by stories of each major character.
