The Initiation by Chris Babu

Published two years before Covid, The Initiation is set a generation after an apocalypse that featured a global pandemic, a mass exodus from NYC, strict quarantines, riots over inequality, and federal forces brought in to restore order. Want to know what happens next?
Manhattan is now known as New America, a fully walled-in society based on equality. But the perfect facade hides a dark truth.
A timid math geek, sixteen-year-old Drayden watches his life crumble when his beloved mother is exiled. The mystery of her banishment leads him to a sinister secret: New America is in trouble, and every one of its citizens is in jeopardy.
With time running out, he enters the Initiation. It's a test within the empty subway tunnels--a perilous journey of puzzles and deadly physical trials. Winners join the ruling Bureau and move to its safe haven. But failure means death. Can Drayden conquer the Initiation, or is salvation out of his grasp?