Well, it could be that Gilgamesh is transported to a modern world. He might struggle with the new technology and social norms. For example, he could be baffled by smartphones and the concept of social media. Maybe he uses his ancient wisdom and strength to become a sort of protector in this new world, facing off against new threats that are a mix of modern evils and magical creatures that exist in this new world due to some strange rift between dimensions.
Perhaps in the 'gilgamesh in another world fanfiction', Gilgamesh finds himself in a fantasy world that is different from his own. He could meet new races like elves and dwarves. He may initially try to assert his dominance as he did in his original world. But then he realizes that he needs to form alliances to survive. He could start to learn new magic or skills specific to this world and use his own knowledge of combat and strategy to rise to a position of power and influence within this new world.
If you want the clearest chapter reference, go to Chapter 172. Early on, Not only Shu Yan, but the entire internet was shocked when they saw Su...; later, the chapter leans on Damn, what brand of make-up is Su Yinwan using?.
A practical answer is Chapter 151, because it turns the idea into a concrete scene. The chapter opens with Now it was Zhang Cheng's turn to be confused., adds pressure through going to be able to stay after all?, and ends on I will have my assistant pay the bill..
The best chapter pointer here is Chapter 194, "Come and Exercise with Little Shang". It opens with Director Sun, this isn't another one of your production team's wicked... and closes on Wen Jiaojiao is currently in the next live broadcast room, gloating about....
If you want the clearest chapter reference, go to Chapter 187. Early on, During the competition, she passed by him numerous times, unfazed by...; later, the chapter leans on There was no visible trace of desperation on her face, yet her presence....
The best chapter pointer here is Chapter 169, "This is What Happens to Show-offs!". It opens with Everyone: "What?!" Seeing the shocked and bewildered expressions on their... and closes on Wen Jiaojiao, as if to prove herself to Jiang Li, rolled up her sleeves....
A practical answer is Chapter 144, because it turns the idea into a concrete scene. The chapter opens with Ordinary people would have been at a loss in this situation by now., adds pressure through You people must be reincarnated from starving ghosts—such fast eaters., and ends on He then noticed.
Chapter 160 is the strongest chapter-level answer because it starts from As the sky gradually darkened, the originally mild drizzle began to... and follows through on Then came Shu Yan and Jiang Li, while He Yun silently moved to the back of....
Chapter 177 is the strongest chapter-level answer because it starts from I'm actually the last?!" After the scores were announced, Wen Jiaojiao's... and follows through on It was with great difficulty that she had gained a wave of fans in the....
A practical answer is Chapter 174, because it turns the idea into a concrete scene. The chapter opens with Does Young Master Jiang really care why I would come here?, adds pressure through My clothes were soaked, and I was too uncomfortable if I didn't change., and ends on She knows the camera is.