Why would Harry and Ginny choose to secretly run away in fanfiction?

Well, one possible plot could be that they run away to escape some sort of dark threat at Hogwarts. Maybe a new dark wizard has emerged and they feel that the school is no longer safe. So, they secretly gather some supplies, use magic to disguise their departure, and head off to a remote location like a hidden wizarding village in the mountains. There they try to find a way to fight the threat from afar while also exploring their relationship in a more private setting.

They might run away because they want to explore the wizarding world on their own terms. Without the restrictions of Hogwarts or the watchful eyes of the Ministry of Magic.

Maybe for love. They might have fallen deeply in love and want to be away from the prying eyes of the wizarding world.

The remaining Death Eaters could be the antagonists. Even though Voldemort is gone, there could be some who still hold a grudge against Harry and want to finish what their master started. They might track Harry and Ginny down as they run away, creating dangerous situations for the couple.

One possible plot could be that they run away to escape some dark magic threat that Voldemort's remaining followers are planning. They might go into hiding in a remote wizarding village, where they have to learn to fend for themselves without the help of the Order of the Phoenix. Along the way, they could discover new magical abilities or ancient spells that help them in their fight against the dark forces.

Love. Naruto may finally realize his true feelings for Hinata and want to be away from the chaos of the village to be with her in peace.

They might choose to run away because they want privacy. After all the battles and saving the world multiple times, they just want some time alone without any interruptions from other demigods or the gods. So running away seems like a good option.

Ginny would likely be protective. She loves Harry and knows about his difficult past with the Dursleys. So she would probably stand up for him right away, not tolerating any of their mean remarks.

One reason could be to escape the public spotlight. After the war, Harry is a hero and Ginny is his girlfriend. They might feel overwhelmed by all the attention and want a quiet life, so they run away.

One reason could be to escape the constant media attention and pressure that comes with being in the wizarding world's spotlight. Harry especially has always had the eyes of the public on him, and running away might be a way to get some peace.