Another idea is that there is a prophecy about the two of them saving the village from a great threat. They initially don't believe it, but as strange events start to occur, they begin to accept their fate and train hard to be able to face the oncoming danger.
Perhaps a fanfic where Sakura and Futa are old friends, and Sarada is initially suspicious of Futa. But as the story progresses, they all learn from each other. For example, Futa teaches Sarada some unconventional fighting techniques, while Sakura imparts her medical ninjutsu knowledge to Futa.
Maybe a story where an enemy targets Sarada to get to Naruto and Sakura. Naruto and Sakura then have to put aside all their differences and past issues to protect their daughter. This could involve flashbacks to their own relationship history and how they overcame obstacles in the past. It could also show Sarada realizing the depth of her parents' love for each other and for her.
Maybe they could be in a magical world where Hinata has some sort of time - stopping power and Sakura has the ability to heal any magical wounds. They are on a quest to find a lost magical artifact. Along the way, they discover that their powers work better in harmony when they are closer to each other, which leads to a development of their relationship.
A more emotional plot could be centered around family. Sarada has some doubts about her family, and Naruto and Sakura, having been through their own family - related struggles, could offer her advice and support. They could share their stories of growing up without parents (in Naruto's case) or with a complex family situation (in Sakura's case), which would help Sarada come to terms with her own family issues.
One plot idea could be Sarada trying to learn more about her father Sasuke's past adventures. She could ask Sakura for stories, and together they could go on a small journey to a place important to Sasuke's past. This would strengthen their family bond.
One idea could be a time - travel plot where Boruto and Sarada are sent back to Naruto and Sakura's genin days. They could witness the early days of Team 7 and get involved in some of their missions, which would change the course of history in unexpected ways.
The relationship between the characters makes it interesting. Sakura's experience and Sarada's potential for growth create a great dynamic. Their interactions can be full of emotion and character development.
For Sakura, you could focus on her growth as a ninja and how she imparts her knowledge to Sarada. For example, show her teaching Sarada some of her signature medical ninjutsu techniques.
One idea could be exploring how Sasuke and Sakura adjust to the impending parenthood while also dealing with their ninja duties. Maybe Sasuke is away on a mission and Sakura has to handle the pregnancy alone for a while, which makes her stronger and more independent.
A third idea could be a story where Sarada discovers a hidden power within herself, and Naruto is the only one who can help her control it. This could lead to a deep bond between them as they work together to master this new power, and Sarada learns more about the Hokage Naruto than she ever knew before.