I Log In Alone (2020)

Blurb:
An impenetrable, floating castle has appeared above the city. Only the chosen may enter, and only the chosen will receive the wings to clear the castle. After ten years of trying, Siwoo Jeong has yet to be chosen, but he’s sure his inhuman strength makes him a strong candidate. One day, a player literally drops from the sky and the chance encounter becomes the opening Siwoo’s been waiting for.

Source: www.anisearch.com/manga/56254