Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
Such idol drama plots were more common and usually attracted the attention and love of many young readers. The male lead was a rich second-generation heir, which meant that he was a child from a rich family background with superior material conditions and life experience. The female lead was Cinderella, which meant that she was born poor but gradually achieved success and happiness through her own efforts and opportunities.
Such plots usually involved love, friendship, family, and other topics, as well as business, wealth, power, and other social topics. The readers can experience different characters and plots in the novel, feel all kinds of challenges and opportunities in life, and at the same time, they can also gain emotional and spiritual satisfaction.
It's hard to pinpoint exactly where Gojo is at any given time in the manga. His whereabouts change as the story progresses and different scenarios unfold. It could be in a supernatural realm, a mission site, or interacting with other characters.