People lived in hot deserts without AC or melting their skin off for thousands of years.

You maximize shade, maximize plant cover, maximize wind carrying away heat, maximize heat being reflected or radiated away. That means you implement passive cooling techniques like wind catchers or qanats, build narrow streets to shade the ground, make everything brightly colored, you have as many trees as possible, open waters for evaporative cooling etc..

You can do that in modern times too, look at Masdar city. US city planning is just completeley backwards. You can't plop the same city that "works" in a temperate climate and expect it to work in a desert.