In many 'gojo and utahime fanfic', a frequent theme is the power dynamic. Gojo is extremely powerful, and Utahime has her own abilities. Fanfics play with how this power difference affects their interactions. Also, the theme of hidden feelings is quite common. They might not show their true emotions openly, and fanfics like to dig into that and bring those feelings to the surface. Moreover, the theme of teamwork and how they can rely on each other in difficult situations is also often explored.
Another theme is the exploration of their different personalities. Megumi is more reserved while Gojo is outgoing and flamboyant. Fanfictions often play with how these two personalities interact and complement each other.