Nishuume Cheat no Tensei Madoushi - Saikyou ga 1000-nengo ni Tensei Shitara, Jinsei Yoyuu Sugimashita

A troubled wizard, too strong for this world, resolves to end his life now and return a millennium later, troubled by his overpowering strength. Nevertheless, he finds himself in a world where magic knowledge and application have severely declined, shattering his hopes of finding someone stronger than him. The wizard, now going by Kurt, meets Lala, a girl, and she urges him to enroll in the magic academy in the royal capital. This is made possible by the fact that Kurt can still use the powers he acquired in a previous life. There, he makes new friends and enemies and faces new obstacles in his new realm, but this second existence might just provide Kurt, the cheat wizard, with the joy he so badly seeks!