Brainwaves — Barbara G. Tarn

Bel lives in Rainbow Town, a multi-level underground settlement for survivors of the Apocalypse that wiped out 21st century civilization. She shouldn't have a care in the world, pampered as she is by technology, but she still misses her ex boyfriend. And when she tries to contact him, he is nowhere to be found.
The Wanderlust Bug has bitten Raj who feels uncomfortable in Rainbow Town, and not only because his ex moved on. His memory losses leave him uneasy and he wishes to go out in the great unknown, even if it might mean certain death.
With the help of Shani, who has broken into the forbidden Darknet, Bel and Raj are truth seekers in a too perfect town that feels more and more like a golden prison.
A standalone post-apocalypse novel exploring the future of Earth.