We didn't advance in intelligence, at all, as that's "the capacity for, with information and tools, find a way to put them to use". And the human mind is as sharp as it's always been.

We had less information, and because of that no knowledge of how to make better tools, but if you gave someone from 5000 years ago the information and tools, they would be intelligent enough to figure out how to use them without instruction.

A fun example of that, there's been time and again where prototypes of things we now think of as modern were made about 2000 years before. But they didn't have the prerequisite tools and information to make it anything more than that.

Like "Hero's Engine ", a thousand of years old toy that's a fully working Steam Engine. But cause they weren't good enough at metallurgy yet, they knew it could work bigger but didn't have any methods to make it bigger

A fun example of that, there's been time and again where prototypes of things we now think of as modern were made thousands of years before. But they didn't have the prerequisite tools and information to make it anything more than a prototype.

Like "Hero's Engine", a thousand of years old toy that's a fully working Bronze Steam Engine, but it's basically like 10cm in size. But cause they weren't good enough at metallurgy yet, they knew it could work bigger but didn't have any methods to make it bigger (copper and bronze can't handle the strain that anything bigger than that would make, and that's all they knew how to use at the time)