If you're looking for manga similar to Reincarnation of the Unrivalled Time Mage: The Underachiever at the Magic Academy Turns Out to Be the Strongest Mage Who Controls Time! (Light Novel), you might like these titles.
Allen, an eight-year-old boy from a poor family in the royal capital, is living a poor but happy life together with his mother. One day, however, memories of his previous life suddenly come back to him and he remembers that he is in an dating sim game and that the capital will be destroyed by war if he doesn’t do something about it. If this continues, both he and his mother will be killed! With a sense of urgency, he decides to rise to the occasion in order to save his precious mother’s life and save his favorite character, the villainous young lady Anastasia, the only girl he liked in the game, from her all too tragic and ruinous end.
At the age of 18, everyone is given a skill. The son of the Sword Saint – Arios Macba was expected to be given the strongest skill. However, the skill given to him was “Cheat Code Manipulation”, which was thought to be a miss skill. On the other hand, an orphaned child who was present at the scene developed the skill of the “Silver Sword Saint”, and Arios’ father tried to take him in. In fact, even when Arios activated his skill, it could only increase his attack power. Because of this, he is banished from his family home… but with each battle, he learns too many powers one after the other, and he literally learns to use all kinds of cheats. What’s more, he has become friends with the Second Princess…?