The hardest thing about writing fantasy isn’t the world-building.
It isn’t the language.
It’s not the basics, like the grammar or the punctuation.
No, the hardest thing about writing fantasy is making it meaningful.
Game of Thrones isn’t great solely because it’s entertaining. It has something to say about the nature of power and the desperate, violent things people will do when the only thing they know is desperation and violence.
Harry Potter isn’t about an orphan learning magic. It’s about standing up to authoritarian power, and the friendships and relationships that can give you the strength to do it.
Some of the best fantasy novels aren’t as popular but they are even more meaningful. Anything by Ursula K. LeGuin, for example.
It isn’t necessary to write to educate or enlighten. There’s nothing wrong with writing to entertain. But the best entertainment, whether it’s stand-up comedy or film or art, always connects on a deeper level.
From the outside, it may seem easy.
In my experience, it ain’t.