I LOVE THIS QUESTION!! i think it's the relationship dynamics that differs to how sukuna acts around the pairs. gojo always tries to connect to sukuna as a human / an equal which means they often butt heads and sukunas fighting for his life to remain unbothered. The angst and one sidedness of it is my fave to explore especially with gojo wanting connection and sukuna not being able to give it in a way he'd want. For tjkn how sukuna reacted to heavenly restrictions and toji basically being his ultimate fight because he's new and exciting + how he can't sense toji gets me baddd, them both being haters & their how their personalities would mesh is something I find soooo fun to write. They're both very different but I love them both sooo much :D