One possible reason could be a disruption in her chakra control. If she has some internal blockage or instability in her chakra system, it might prevent her from using it for healing. For example, she could have been affected by a curse or some sort of dark chakra influence that throws off her normal chakra functions.
It might create more conflict. Since she can't heal, the group she is in will face more challenges when they get injured. This can lead to difficult decisions about whether to continue their mission or retreat, adding more tension to the story.
Sakura could also develop her chakra by exploring her family heritage in fanfiction. Maybe there are hidden techniques or ways of chakra manipulation that her ancestors knew. By delving into her family's past, she discovers a special type of chakra meditation that helps her unlock more of her potential. This could involve visualizing her chakra as a sakura tree, with each branch representing a different aspect of her power, and as she focuses, the tree grows stronger and so does her chakra.
One possible plot twist could be that Sakura discovers a hidden power within herself that is even more powerful than her healing chakra. Maybe it's a dormant bloodline limit that gets activated due to the loss of her healing ability.
Maybe he starts by observing Sakura's current chakra control. He might notice her flaws and then begin with basic chakra exercises to improve her stability.
There might be a sakura chakra fanfiction where Sakura's chakra is somehow mixed with a foreign energy source. This causes her chakra to mutate and gain new properties. She may find that she can now use her chakra to create force fields that not only protect her but also those around her. This new form of chakra also makes her a target for various groups who either want to study it or use it for their own malicious purposes.
Well, it would make her more vulnerable. Without the ability to use healing chakra, Sakura can't rely on her usual means of helping in battles. She might become more cautious and start to focus on other aspects of her skills, like physical combat or strategic planning. This could lead to a more complex and interesting character as she has to adapt to this new limitation.
It could be that in the fanfic world, Sakura received some advanced training or magical knowledge that enabled her to perform such a feat at a young age. Maybe there was a unique circumstance that triggered her healing powers specifically for Kakashi.
He might rely on his physical strength and martial arts skills. Naruto is known for his tenacity and determination. Without chakra, he could train his body to be extremely strong, like a super - athlete. He could use his speed and agility to dodge attacks and land powerful punches and kicks.
One interesting fanfiction could be where Sakura's ability to see chakra leads her to discover hidden powers within herself. She might start seeing chakra in a completely new way that no one else in the Naruto universe has ever seen, and this could lead to her developing unique jutsu.