Level Up: The Knockout (Book #1): LitRPG Series

Mike Hagen, an American nicknamed "Crybaby," became one of those chosen to be given an augmented reality interface. However, his favorite game was an MMA fighter—possibly, for the reason that he'd never fought in real life, and the interface adapted itself to him.
Will Hagen be able to use it right? And will it help him to crawl out of the dreary pit of his existence?