I mean, sure, the dictionary definition says "created directly and personally by a particular artist; not a copy or imitation", and I agree with that, but hear me out, I like these philosophical rabbit holes.

The definition says "not a copy or imitation", so we are presupposing that those things exist, so something original is the antithesis of a copy or imitation.

Now imagine if absolutely everything is original, wouldn't the word lose its meaning? Isn't something original the opposite of a copy? If no copies exist wouldn't it be the opposite of nothing? Or even itself?

Original things wouldn't be original, they would just be.