The mystery around his speech. Since Toge Inumaki can only speak in onigiri ingredients, fanfics that try to dig deeper into how he really feels and what he wants to say but can't in the normal way are always interesting. It gives the writer a chance to be really creative in showing his internal dialogue.
Well, one way this could work in a fanfiction is that Naruto could use Yuta's powers to enhance his combat abilities. Yuta has some really unique and powerful cursed energy techniques. Naruto might be able to combine his chakra with Yuta's powers, like using the Rasengan with Yuta's cursed energy for a super - powered attack. It could make for some really interesting battles against tough opponents like Madara or Kaguya.
It's hard to give an exact time as it depends on the manga's plot development. But typically, Yuta Okkotsu shows up when certain events and character arcs lead to his introduction.
One great toge inumaki fanfic is 'The Cursed Words of Toge Inumaki'. It delves into his character's struggle with his unique form of communication and his relationships within the Jujutsu Kaisen world. The author does a wonderful job of showing his inner thoughts and emotions despite his limited speech.
If Naruto had Yuta's powers, his fighting style would be drastically different. He'd no longer rely solely on ninjutsu and taijutsu. He could use Yuta's cursed energy to create new types of attacks. For example, he might be able to send out waves of cursed energy like Yuta does, which could catch enemies off guard. This would make him a more versatile fighter and a greater threat to his enemies.