In a straight - up fight, Itachi has some very powerful abilities. His genjutsu can be extremely difficult to break out of, and his ninjutsu attacks are strong. But Batman is no slouch. He has fought against some of the most powerful villains in the DC universe. He would study Itachi's moves and try to find a pattern. Batman might also use his wealth to create some sort of countermeasure to Itachi's Sharingan. Overall, it's a very close call and would likely depend on how the writer of the fanfiction wants the story to go.
Sukuna does die in the manga. The way it happens is quite dramatic and ties in with many other elements of the story, adding depth and tension to the overall narrative.
One interesting scenario could be a battle in a dark, abandoned cityscape. Itachi's Sharingan abilities would give him an edge in terms of perception and illusions. Batman, on the other hand, would rely on his gadgets and combat skills. He might use smoke bombs to disrupt Itachi's line of sight and then try to get in close with his martial arts. Another scenario could be a mental battle. Itachi is used to psychological warfare, but Batman is also a master of getting into his opponents' heads. Itachi might try to use his genjutsu to break Batman's will, but Batman's strong mental discipline could resist it.
One interesting scenario could be a battle of wits. Itachi is known for his intelligence and Sakura has grown to be a very smart and capable ninja. They might engage in a mental duel where they try to outmaneuver each other with strategic moves and mind games.
No. Ryomen Sukuna is a fictional character from Japanese mythology and modern manga/anime. He doesn't have a basis in a true historical event or person.
Nope. Ryomen Sukuna has no basis in reality. It's a product of the creative minds of the writers and illustrators who designed a captivating fictional character for the enjoyment of the audience.