Curate, connect, and discover
Something I love about writing fantasy that includes multiple nations/kingdoms/cultures is the small character interactions between people from different places
An example from my own work is the way two people from different kingdoms drink tea. One puts the leaves in the cup and pours the hot water over it, and the other steeps the leaves in the pot. The one who has the leaves in the cup always explained it as “if someone doesn’t want tea, they can have hot water instead.” And the other kind of just, watches thinking, “this is odd, but it’s genius”
So yeah, cultural differences lead to fun character interactions
(I deal with this irl through teaching my white friends how to eat Asian food)