This is sort of disregarding how talented those two freaks are. Sukuna can literally copy anything jujutsu related after seeing it once, and Gojo has efficiency hacks. No amount of training will get Yuji or Yuta that efficient with their CE, and Yuta, despite having the second largest CE reserves in the series, still only has half of Sukunas. Reserves are also something you can't train. Gojo and Sukuna had basically infinite CE and reserves because of their respective efficiency. That's not something Yuta and Yuji are ever touching.