Some people object to using a modifier like "very" or "a little" with the adjective "unique". They say that "unique" means "one of a kind", and that is a strict binary.
Well, they're wrong. "Unique" is not a strict binary. As with most other things, it's a continuum, and things can be more or less unique.
For example, consider the Wright brothers. They built bicycles. At first, their bicycles we made using the same designs as any other bicycle. It would be safe to say they weren't unique. But the Wright brothers were inventive fellows, and they came up with ways to improve the design of their bicycles. At that point, their bicycles were unique. There were no other bicycles like them. Then they built an even more unique machine. A machine that did something no previous machine had done. The bicycles were unique, but they were still bicycles. The airplane was a whole new thing.
Another example. Consider two books. One is full of old tropes and tired clichés. Utterly predictable, but not plagiarized. It's not unique in that it mimics other books, but it is unique in that it consists of a sequence of words that had never been written before. The other book is more original. It's unique in that no other book has a similar plot, but it's not unique in that it still consists of words printed on paper. The latter book is more unique than the first.
There are many ways something can be one of kind, and the more ways that apply, the more unique a thing is.