If you loved Sumikko Gurashi: The Pop-up Book and the Secret Child, try Friends: Naki on Monster Island
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.
You already loved

Sumikko Gurashi: The Pop-up Book and the Secret Child
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Friends: Naki on Monster Island
What they share
Theyboth carry the cozy mood tag, and they sit in Animation / Family territory. If that's the register that drew you to Sumikko Gurashi: The Pop-up Book and the Secret Child, the second film will land in a comparable space — through a different lens.
cozy
What Friends: Naki on Monster Island is
Mushroom stumbles onto a fog-shrouded monster island where the locals faint at human contact. Once discovered, the monsters panic harder than the kid ever could. At least the island’s animators had experience with terrified facial expressions.