After Regression, I'm a Fifth Grader

Once hailed as a “soccer prodigy” from the age of five, the protagonist lost everything in a devastating accident—only to regress back to the fifth grade. When he gives up a guaranteed path to success and saves a child once again, the system rewards him with injury recovery, while the rescued child’s grandfather offers him unlimited backing. The catch? Inside this elementary schooler is a sly middle-aged man living his second life.