Jujutsu talent is directly linked to how much you know and what you can do with it.
Even the most talented individuals don't present themselves as innovators, they simply excel in applying existing techniques.
Rarely in JJK do you see someone do something brand-new and completely unheard of — but theoretically possible. For example, Gojo shrinking his domain; it's something only he could have done, but once Yuta saw it, he applied it to himself too.
The ability to create is not linked with Jujutsu. You just need to stretch the rules as much as you possibly can in your favor, and the system shows this by directly stating that omittion = mastery. No one is expected to do anything new, but simply do the existing in the best manner possible.
Dabura, for one, had full mastery of his CT based on what he knew. He was insanely efficient, and learned more about his technique through battle, but never invented a new concept of Jujutsu, but simply applied it in a better manner.
The biggest example of innate Jujutsu talent is Sukuna, due to his ability to simply do anything by seeing it once. Having complete mastery over something, seeing something completely new and being able to apply it without external help is the essence of Jujutsu talent.
He never invented anything, but did literal impossibilities because he understood them. Higuruma, Dabura, Gojo, Yuta, etc. all do the exact same, but none of them were able to simply do ANYTHING.
Sukuna is the only character that I can see, where if you put him in any situation where something is even remotely possible, i.e opening a barrierless domain, cutting existence, resuming a reincarnation process, he would be able to replicate it.
Most talented Jujutsu Kaisen characters