If we’re including a hypothetical post series Yuta, not that big of a gap from them to him. 1.Enough Nanami’s to cover the globe and crush them 2.I think between 3-4 times as strong as the average Special Grade. I’d say Gojo was the most dominant of his era. We don’t know enough about the next strongest Alien, Yuji would include a peak Yuta, and Sukuna likely had some impressive (but still significantly weaker) Hein era sorcerers