Nethersteel
I know I opened the debate about shadow power, but I think you should choose for yourself, do you feel better writing about that power? Do you want to develop it in the Naruto universe? Do it, do what you like more. Write what motivates and interests you the most. I prefer you to write only Naruto elements, but you should do what makes you happy, it's your story.
I think you can keep it, but maybe change it a bit. You said it takes a really long time to learn how to use it, but we’re in the naruto verse. There are teenagers beating gods, and boruto has probably even more talent. By the time boruto learns how to use the shadow energy, he is already a god level shinobi.