Might look even better a slight edge fade effect on the stream's borders.
And maybe something to "integrate" the cliffs a bit better (manual shadows and / or a different ground texture w. edge fade around them).
The biggest dificult with cliffs, in my opinion, is that white edge they have. It's difficult to integrate with any terrain I've tried. The marked limit always appears
If you ever want to get rid of that part you could try adding more terrain fills on a sheet above the cliffs with a small edge fade.
Have you also tried adding a slight edge fade directly to the cliffs?
Just checked some of my older maps. An "Edge fade inner"-effect with 0.5m edge with seems to work quite well to help the cliffs blend in.
Another thing that might work is a Color Key sheet effect if you are willing to carefully draw a cutout poly along the top edges of the cliff.
Careful and Ricko don't mix 🤣