A illusory effect of Photoshop in creating photos

Original:

Open the original image, copy the background layer:

Enter the channel, click on the blue channel, perform "select" => "Color range" and click on the blue sky with the eyedropper:

After saving the selection, click the RGB channel directly with the mouse

Go back to the layers panel and add a mask directly to the layer:

Select the background layer, enter the channel panel, select the red channel, press CTRL + a all, and press CTRL + A to copy:

Go back to the layers panel press CTRL + V to paste and adjust the opacity of the layer:

Merge layer 1 and Layer 2, and then copy a layer, select the copied layer, and perform the filter => "blur" => "Gaussian blur":

To adjust the opacity of a layer:

Flatten all layers to the final effect: