From Overshadowed to Overpowered: Second Reincarnation of a Talentless Sage

Story

Ephtal is reincarnated as a human, coming from modern Earth. In this new world where magic is real, he decides to devote the entirety of his life in the pursuit of magic. Despite his efforts, though, he discovers that he is absolutely talentless in magic, and breathed his last in anguish....But it isn't the end for him just yet! He reincarnates once again bearing the same name, Ephtal, 400 years later. Having retained his knowledge and power, he steals his resolve and once again sets his sights for the peak of magic!

Synopsis via AniList (English).