Harry Potter: Zip It and Get to Work Building the Future

[The protagonist has no romantic pairing, though there is GGAD. She starts out as a little mute, but gets better later. The pacing is slow-burn, very slow-burn, extremely slow-burn. This is not a power fantasy.]

From the moment she arrived in this world, Sevra knew one thing:

Grindelwald was ill, seriously ill. He'd suddenly lose it and turn into a completely different person.

So Sevra stayed by Dumbledore's side until she was eleven, then enrolled at Hogwarts.

In her first year, Sevra went night-riding with Walpole. She was charging through the pipes in high spirits when Snape caught her red-handed.

Still in her first year, Sevra and Walpole barbecued in the pipes. Meanwhile, Hogwarts gained its own nightly roar.

In her second year, Sevra borrowed the Marauder's Map and made sure every Hogwarts student acquired a suitably grand nickname.

In her third year, Dumbledore entrusted Sevra with welcoming Harry to Hogwarts. She succeeded in making Snape hate her even more.

In her fourth year, Sevra tricked the diary into practicing Chinese cultivation techniques, then castrated herself.

In her fifth year, Sevra finally learned to speak. The first thing she learned to say was dog-talk.

In her sixth year, Sevra finally managed to say her first words to the noseless man. She was so moved she could have cried.

Seventh year: Sevra never had one.