That's wallpaper that is actually flat but creating the illusion of dimension. Look at how the light from the wall sconce does not create shadows on the visually varying heights of the design. Also, no varying heights on the outside corner of the wall.

Now, where to find the wallpaper, right? You could start with google image search to find brands of wallpaper that do this sort of thing. A good source to start with is https://www.archiproducts.com/en/products/wallpapers

Ah good point. Thanks for the help I’ll be looking!