I'm searching either for one story for for two stories. I'm not sure if the following are part of the same one, or if I'm conflating two things.
Harry something something meditated and has super control of his magic. He compressed his cores, has multiple cores, rebuilt his entire body, the troll became a friend/adopted brother. He created some sort of super spell for library searching. He's friends with Daphne and Tracey, among others and helped them build mindscapes. He either co-opted or took down a criminal family. Petunia is some type of squib/is nice.
I'm not even sure that this is a HP fanfic, but it can't be anything else. Harry can somehow mind read? Copy other people's minds or pieces, and he uses that to have various language modules in his brain. I think he also has a metamorphmagus module, and maybe he travels. I think he can share? He can copy his language modules and give them to other people do they can learn the language. It's not Xerosis by Batsutousai, though. I think he also makes Hedwig supersmart? Some sort of animal empathy/control/I'm getting animorphs or Pokemon vibes.