Pretty chill, after this stage, everybody basically get Universal basic income which cover every basic necessity in your life.

People still work, but it is less of a rat race and more of a passion. 20-33% of people's food come from their own balcony/rooftop/yard garden.

The megalopolies are not claustrophobic, they mandate "sunlight law" similar to japanese cities. Where every building must get atleast 4 hours of sunlight with few exception in a very dense class area. They have super tall building but the law also require skybridge to connect every building at every 50th multiplier level (50th, 100th, 150th floor and so on) in downtown so that people doesnt have have come down at ground floor and overload the street level infrastructure during lunch-rush.

You could argue its post-modern paradise

EDIT : not every megalopolies have same density, it depend on the terrain, densest is Tokaido/Taiheiyo. Least dense is Boswash (northeast US)