How can we dehaze a photo with curves and not using Dehaze?

The correction itself is easy to do with Levels.

But remember what atmospheric haze is. It increases with distance. Dehaze is specifically targeted to the areas of the image with low dynamic range, which in a landscape shot is whatever is far away, and more adjustment the farther it is. It is auto masked.

In other words - in Photoshop you need masking.