The uncertain last active protected or armoured cruiser

Which protected or armoured cruiser remained in active service the longest?

ARA Pueyrredón is offered as the probable answer, but active service rather than nominal commission still needs verification.

The discussion distinguishes a ship that remained formally commissioned from one still capable of going to sea. That difference prevents a service-end date from settling which protected or armoured cruiser lasted longest in active use. A viewer proposes ARA Pueyrredón, decommissioned in August 1954, and the suggestion is accepted as probably correct. The identification remains provisional because no supporting research is carried out during the stream.