Cyberpunk is more than just post apocalyptic aesthetics like Blade Runner.

Robocop, for example, was in the Cyberpunk genre. Johnny Mnemonic, also a cyberpunk.

Basically, cyberpunk is a world where the Governments have collapsed or have been abolished by corporations that run the entire world. The wage gap between the poor and the elite is so far they may as be between America and Africa. Only it's all happening in the same city. Another good example is the movie In Time (2011) with Justin Timberlake. Not necessarily a post apocalyptic setting.

The lower level citizens are fighting to compete for space and power, being handed down technology and resources that the elite throw away.

In Cyberpunk 2077, most of the world is barren is dead. And humans only live in giant megacities around the world, packed so densely inside you may have 10,000 people in a single 100 story apartment building. And inside the building is its own community, with stores like restaurants and barbers, and even some have schools and parks in them.

The game obviously couldn't translate 1:1 exactly the world that Mike Pondsmith created because of technology limits like CPU and GPU rendering power, but it's a very close approximation.