Gojo was up there with the strongest individuals in the world of Jujutsu Kaisen. In fact, he was widely renowned as the strongest modern sorcerer, and he was able to his own against the King of Curses, Ryomen Sukuna. In fact, Gojo and Sukuna were almost neck and neck in terms of strength, and even though Gojo lost his battle to him, on another day, he could potentially have won. Of course, the plot required Gojo to lose, and that is why he ended up losing the battle against him.