The Otherworlder, Exploring the Dungeon(2019)

Ihoujin, Dungeon ni Kuguru.

Broke and desperate, Souta signs up for a gig to warp to a fantasy world and ascend a dungeon tower to claim the treasure inside. However, an accident in the transfer process separates him from his teammates, leaving him stranded. Will his adventure end before it even begins?

(Source: Yen Press)