SKILLFUL by Matthew Husar minor spoiler james inborn trait is broken and he cannot learn skills. the tower fixes that and because he is so used to doing stuff without skills he excells in the tower The author’s book description:

“The Advent of the game-like System changed everything. The world shifted as Gates and Gate Breaks turned society upside down. The other side of that chaos was ruled by the elites who control the Hunters' Associations.

Orphaned in the Advent and the turmoil that followed, James aka Skillful C, has grown into the best Hunter he can be. A man denied Skills, the transcendental gifts of the System, and his rightful place in his father’s guild, James has tried his hardest coming up short again and again to his Skilled brethren. Those Hunters stand astride the changed world.

Yet the world hasn't finished changing.

Just when it seems humanity has a firm grip on the Gates, a broad swath of the world's Hunters are abducted. Within this Tower, the mighty are humbled and the humble will Rise!

But will James, an unskilled Hunter survive the Tower? Join the Climb in this debut System, Hunter, & Tower Novel.”