2. The language and numerical values suggests it's Gojo; the narration never claims that Utahime and Gojo together brought the Hollow Purple to 200% but that Gojo, via performing the same ritual as Utahime, "brought" his technique up to 200%. This language could not mean much, could just be a cooler wording choice, but then you also notice the numerical values. Utahime amplifying Gojo's CT by 120%, then Gojo amplifying it by a further 120%, we get.... 200%? That's not very coherent, it should be 144%. Well, maybe the narration actually meant that Utahime was amplifying her own CT by 120%, and so the degree to which her own CT aids her allies is unknowable. So where x is the standard amplification of the CT, we get (x * 1.2) * 1.2 = 2, aka Utahime's CT amplifies people's output by 138.888888888.... It's definitely possible, but kind of an odd figure and overall odd interpretation imo. I'm not ruling it out, just saying it doesn't appear as probable here given the randomness of it.