When did Tolkien ever describe Galadriel as a warrior in plate armor?
A strong wise leader yes but an sword swinging soldier? Never.
During the First Age Galadriel was a leader (of armies) during the Noldor rebellion and the Wars of Beleriand. Tolkien described her as “the only female to stand tall in those days.”
I suppose it’s possible she wore her nightgown into battle in the First Age...