If you loved Luffy's Fall! The Unexplored Region - Grand Adventure in the Ocean's Navel, try One Piece: Curse of the Sacred Sword
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.

Luffy's Fall! The Unexplored Region - Grand Adventure in the Ocean's Navel

One Piece: Curse of the Sacred Sword
What they share
Theyboth carry the playful, uplifting mood tags, and they sit in Action / Adventure / Animation territory. If that's the register that drew you to Luffy's Fall! The Unexplored Region - Grand Adventure in the Ocean's Navel, the second film will land in a comparable space — through a different lens.
What One Piece: Curse of the Sacred Sword is
In a fishing village near a sealed shrine, you guard the Seven Star Sword whose legend brands every thief cursed. When Marines storm the coast, your crew vanishes but Zoro stays behind, sword in hand, eyes empty. You spot him fighting his own past when a face from his swordsman days reappears—Saga, now leading the charge.