Apologies, I tend to ramble on and I obviously wasn't clear. I was suggesting the wavy sand as a replacement for the foreground, lower part instead of the ground texture you have there currently. For the background, a non-textured look is fine. Apologies if I sent you down the wrong path.
I would concentrate on rock placement (as suggested by Eishiya) as it's still looking very regular and unnatural.
See here:
https://www.newsweek.com/life-mars-microbes-chilean-desert-822195Your wavy sand does indeed look wavy. Well done on that!
The waves are on a small scale and you could probably get the same or a better effect with less detail, but it's a great start.
I'm having a think about how I would approach adding texture to the background sand. As it stands, the patches of light and shade you're using are starting to hint at something with shape and form, but they don't quite come together. Imagine you want to get across the idea of the sandy waves, but you don't want to spray that texture all over the background (and parallax would make it look very odd while scrolling anyway.)
However, you've now had practice making your sandy wave shapes, so you could imagine that the occasional wave stands out a little. Maybe it catches the light just right, or it's a bit bigger than the others. How would it affect the scene?
- The bases of the rocks might show build-ups of sand on one side, and wavy bottoms.
- The rock shadows might be disrupted by the waves in the sand.
- You might lightly define short segments of these occasional waves in the sand here and there.
Currently the rocks look a little like they're floating, perhaps because of the flat bottoms and the shadows that seem to be disconnected from the left side of the rocks. Having the sand interact with them and their shadows might help you create a more cohesive scene.
I may make an edit later if I have time.