The World's Strongest Rearguard - Labyrinth Country's Novice Seeker v01-v04 (2020-2022)

English translation of the Japanese manga Sekai Saikyou no Kouei: Meikyuukoku no Shinjin Tansakusha (世界最強の後衛 ～迷宮国の新人探索者～).
Workaholic Atobe Arihito has died and been reborn in "Labyrinth Country" where he's now a dungeon hunter. He enlists in the guild and picks a job title, but while searching for a party to join, it seems no one wants the help of his bizarre job choice, "rear support." He's running out of time to join a group, and when someone finally approaches to offer him a job it's...his ex-boss!? Here starts the adventure of the strongest supporter!