Volumes 1-3 of The World’s Fastest Level Up.
It's a typical cheat skill fantasy story, minus the isekai. The characters go dungeon crawling to level up, gain special skills, and make money. Protag wants to use his cheat skill to rise to the top.
The first volume was okay. Nothing special, but it matched the description and adhered to the premise, so no complaints there. The protagonist wasn't awful (as far as these types of stories go). Just a single-minded guy working solo towards his goal.
Didn't enjoy the second and third volumes as much. The main character devolved into more of an oblivious harem protagonist, and he seemed less consistent in general. Wasn't a fan of the twists in the story or the general direction it's going in either.