What to expect:
In this Alternate Universe story, the focus will not be closely tied to Boruto's narrative. While ninjutsu techniques will be incorporated, shinjutsu or dōjutsu will be excluded from the plot.
There won't be any gender-bending except for Haku, as I believe the character l to be a girl still.
The story will not be a crossover, and the main character (MC) will only possess abilities within the Naruto world. Although the MC is intelligent, they won't be a genius like Orochimaru or Tobirama. They will make mistakes and misjudgments on occasion.
Jutsu will be written in alphabetic Japanese. Like Ninja Style: Clone Technique will be Ninpo: Bunshin no Jutsu.
Dōjutsu Explanation:
Now, let's explore the three main dōjutsu in the story, starting with the Byakugan. These eyes belong to the Hyūga clan, inherited from their ancestor, Hamura Ōtsutsuki, who received them from his mother, Kaguya Ōtsutsuki. The Byakugan is pure and unevolving, so there won't be any Tenseigan in this story. The focus will remain on the original dōjutsu.
The Sharingan, on the other hand, is inherited from the God Tree and was first manifested by Kaguya after consuming the chakra fruit, granting her the Rinne-Sharingan. During this time, Kaguya gives birth to her first child, who manifests the first true sharingan in his main eyes but does not inherit the Byakugan. It's important to clarify that the Sharingan is not a dōjutsu of the Ōtsutsuki clan; it is connected to the Earth's God Tree.
The Sharingan has an evolved form known as the Mangekyou Sharingan, which grants the ability to use the Susanoo and two other unique abilities. Indra, the firstborn son of Hagaromo, is considered the father of the common sharingan.
The third dōjutsu is the Rinnegan. It's crucial to note that the Rinnegan is not an evolution of the Mangekyou Sharingan. Awakening the Rinnegan doesn't involve mixing Senju chakra with Uchiha chakra. Instead, it requires gaining Ōtsutsuki genetics, like Madara and Sasuke, who received the zetsu. Additionally, one needs to acquire the unique chakra infused within pure God Tree chakra (Sage of Six Paths' chakra).
Pure Ōtsutsuki can awaken the Rinnegan by consuming a Chakra fruit or chakra pill, which manifests as an extra eye somewhere on their body. Due to Black Zetsu's meddling, Madara awakened a Rinnegan that was Hagomoro adjacent, explaining why he had access to the Gedō Mazō (Gedo Statue).
Black Zetsu was able to manipulate Asura and Indra's chakra along with whatever chakra was left in the God Tree's roots (I'm sure you saw the connected tendrils) and Hashirama's senjutsu to awaken Madara's Rinnegan. Thus the years it took.
MC power progression:
He's only advantage is chakra manipulation (internal and limited) and chakra sensing. And he is a rich civilian.
Chakra control exercises will be vividly explained in their aim, and elemental transformation will be a pivotal aspect to performing nature jutsu.
He wouldn't be super op due to certain factors mentioned within the story, and he sure as hell won't be focused on maintaining canon events.
This is not a Fix-it fic.
In canon characters I only care about goals, I don't particularly care about their significance to events that might or might not happen, or if their lives are good or not. Expect immediate divergence.