After Returning, My Abilities are Infinite - Chapter 80

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

She, Xue Fanxin, a famous medical genius in the 21st century, had transmigrated into the body of the dumb daughter of the Grand Duke.

Lin Jing had transmigrated.

And he had unlocked a System Space with its own Spirit Field.

Thus...

While others sought out the Secret Realm, he was farming.

While others fought over resources, he was practicing Alchemy.

It was in this way that he slowly grew with the passing years...

Until after countless ages, someone finally realized that the great one was actually him...

This book is also known as:

“First I Farm, Then Do Alchemy, I Seek Immortality by Holding On to Life”