If you loved Road to Ninja: Naruto the Movie, try Naruto: The Lost Story - Mission: Protect the Waterfall Village!
A bridge between a film you've already seen and one most people haven't. Naruto: The Lost Story - Mission: Protect the Waterfall Village! has roughly 7.9× fewer votes than Road to Ninja: Naruto the Movie — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.

Road to Ninja: Naruto the Movie

Naruto: The Lost Story - Mission: Protect the Waterfall Village!
What they share
Both films are directed by Hayato Date, and they sit in Action / Animation territory. If that's the register that drew you to Road to Ninja: Naruto the Movie, the second film will land in a comparable space — through a different lens.
What Naruto: The Lost Story - Mission: Protect the Waterfall Village! is
You're a ninja, tracking thieves who've raided sacred springs. But a rival squad complicates your mission. Date's direction keeps the focus tight. What remains is a question: can loyalty overcome duty?