Bascily something in pixel art style like this. Now this is a side veiw which is different from the top-down im going for but you seem to really hit the nail with intergrating the looks of the ancient desert "3d" style-ish in 2d and effects which I love.
With colour and effect style when needed (shrines, altars, or sacred tree) similair style added as you have used on ancient desert. Personaly I would add some grit or darken / brushed effect to it to make it look older or higher up in the surface air level.