I believe it’s moreso that range isn’t the sole factor if a resonator can break a sonoro sphere. It also a matter of their forte has the ability to break said sonoro sphere, which is not a simple matter of having enough DC to do, it’s the question if their forte had a specific characteristic/ability (or Hax i think) to break down a sonoro sphere, which is not a typical pocket dimension. In Changli’s case, it’s clear that she has both the range and capabilities in her forte to break down the sonoro sphere during her companion quest.
With the example of room-sized sonoro, it’s the case of while Augusta can cover the range, what matters more is if her forte can directly affect a sonoro sphere, which we don’t have any feat for currently for her nor could Changli’s feat apply to her. In this example case, range is irrelevant.
I agree with these, Iuno’s has better AOE than Carlotta, clear on that, but as far as range (how far in terms in distance can they shoot) goes, it’s not too far apart for both to say who can shoot farther. Phrolova’s Sonoro didn’t break down after Hecate’s defeated, it was right as Phrolova is about to be attacked before she undid it. Including character scale to their sonoro sphere is more of a case-by-case thing.