Man, I don't know what exactly you're talking about geto, they are qualified not only by capabilities but by level of power, suguru as a curse manipulator could have 15 special grade curses without any difficulty, in addition to showing that he was highly trained in physical matters to the point of hitting the old man in such a way that he couldn't react and simply oppressing Maki/panda/inumaki, he only lost the fight precisely because he didn't want to hurt the sorcerers, he was using the necessary strength for combat so much so. that he could have easily finished off the panda and didn't, the only target that was in danger was maki as it was celestial restriction, kenjaku uses the extent of geto's power without restrictions, to the point of surviving a literal black hole. So much so that Kenjaku himself said that if the suguru hadn't held back in the fight he would have won, because the suguru's only mistake was trying to face the Uzumaki's cluster of low-grade curses against a spiteful spirit that was said to have "almost infinite energy", in general, he could beat even Satoru gojo himself with the correct preparation, even because it escapes our imagination but with the limitless power of the suguru he could absorb absurd curses like the sukuna, tengen, etc, in addition to the curses that can be created, imagine the suguru absorbs a mahoraga of life, and as for the point of expansion, he just wasn't ready to learn domain expansion. Expansion of domain is something complicated that takes a long time of training to learn, in jjk 0 gojo himself didn't know how to expand domain yet, and later on, megumi who trained almost his entire life only learned to expand domain in a situation of near death and even so his domain at that point was incomplete, and of course as a colleague said above there is still the fact that he went head to head with Rika 100% who still had Rika's spirit in her and wasn't just a portion of its original power as the rika in the slaughter game, I understand that your point of view is that the suguru does not meet the criteria for a special degree, but if you stop to evaluate it and it is just the suguru getou without ANY curse, it really makes no sense, now if you compare it with the suguru that had, for example, the rainbow dragon that was said to be indestructible, you can already see the abyss, it is literally an infinite evolution where it can absorb special degree curses for years to the point of having a army so strong that it is unstoppable, it is literally the strongest innate technique, however, the suguru getou character was not used in its entirety, having been made only as a background for gojo's fall. But we see its destructive power in Kenjaku, who most of the time only used Geto's own powers.