There is no human with all the positive variants; it is the the distribution of these variants that explains 5.2%. GM would allow you to create such a human.

That paper does not imply what you think it implies: that editing all these variants in an individual embryo would have a small effect.

An individual with the top 200 IQ-enhancing variants edited in (and an otherwise normal genome) would be far, far smarter than than than you seem to think, even though the variants edited only explain 5.2% of the differences within the population.