Yes. The conflicts between Sanji and Luffy in the manga often stem from complex circumstances and character developments that drive the narrative forward.
Luffy uses Gear 5 in a significant battle towards the later part of the manga. But the exact chapter or arc can vary depending on how you're reading it.
In fanfics, Admiral Kizaru's power can be highly exaggerated. His Pika Pika no Mi ability, which allows him to move at the speed of light, can be made even more potent. Writers might make him capable of creating stronger light - based attacks or having better control over his speed. For example, he could be shown to split into multiple light - clones more easily and use them in more complex battle strategies.
Another theme is loyalty. Kizaru is often part of a group, and fanfictions explore his loyalty to his comrades. There could be stories where he has to choose between following orders and doing what he believes is right for his friends. This creates interesting moral dilemmas within the story.
Luffy is still alive and kicking in the manga. The story keeps evolving with him at the center of the action, encountering new enemies and growing stronger.