Unclear if it’s a mistake, but Valkyria Revolution and all of its DLC/in-game items are currently free on the PlayStation Network for both PS4 and PS5.
We’re not sure if it’ll last (if it is a mistake) but you can currently add it to your library HERE. If you’re looking for all of the DLC and in-game items, you can find them HERE.
Big thanks for reader and friend of the site Josh for letting us know about this.