Asaokitara Tansakusha ni Natteita no de Dungeon ni Mogutte Miru

Dive into dungeons, level up, and make money! A slightly challenging, classic adventure story! Approximately 30 years have passed since dungeons suddenly appeared in the world. Daichi, a high school graduate and part-time worker, wakes up one morning to find that he has become an "explorer," a person with special abilities. As he gradually gains strength through trial and error in nearby dungeons, his dungeon life begins to change when he meets a female explorer named Kazane.

(Source: Kadocomi, translated)