Yes, there are likely many fanfics out there with the concept of Naruto being at Jonin level. You can check fanfic platforms like Fanfiction.net or Archive of Our Own.
I'm not entirely sure which specific 'neal casal the real story' you're referring to. Neal Casal was a talented musician. He was involved in various music projects. Maybe the real story could be about his journey in the music industry, his creative process, and the people he worked with.
One great young Jonin Naruto fanfic is 'The Ascent of a Young Jonin'. It focuses on Naruto's journey as he transitions into a Jonin, facing new challenges and forming deeper relationships with his friends. The story has some really exciting battle scenes and character development.
New storylines. Fanfics can create unique scenarios. Maybe Naruto has to team up with unlikely allies as a young Jonin to face a powerful enemy that the village has never seen before. It adds an element of excitement and unpredictability.
One possible plot could be Naruto facing new and tougher challenges as a young Jonin. He might be assigned to lead a special mission that requires him to use his unique skills and leadership abilities. For example, he could be sent to a border area where there are constant skirmishes with enemy ninja. Naruto would have to strategize and protect his team members, all while dealing with the expectations that come with being a Jonin.
I'm not sure specifically which 'Neil Casal the real story' you are referring to. Neil Casal was a musician. Maybe it's about his life journey, his musical achievements, or some personal experiences. Without more context, it's hard to give a detailed account.
Sasuke could also be a main character in the 'naruto jonin exams fanfic'. His skills and his rivalry with Naruto would make for an interesting plotline during the exams. Also, Sakura might be a main character as well. She has grown as a ninja and could show off her new abilities during the jonin exams.