The word “unique,” by definition, means exactly this: “one of a kind.”
Imagine saying to someone, “Wow, great outfit. It’s very one of a kind.” Or “Hey man, you have a REALLY one of a kind songwriting style.” It makes no grammatical sense.
Is it one of a kind or not? If it’s kind of like something else you’ve seen before, it’s not unique, period. If it’s kind of like something you’ve seen before, but with something different to it, then it has a unique approach (or whatever). And if it’s truly one of a kind, such that you want to enthuse about it, it’s “unique”.
Not “very” unique. Not “really” unique. Just unique.
Rant over.