You don't need wallpaper, and a 9" splash is fine. Floating shelves is plenty of interest.......but not as you have them on the rendering....too long, static, top one too high . Not to mention you have open shelving elsewhere in the kitchen.

what's going on here?Maybe the doors are missing?or were damaged?

Either put doors on the left......, or use 2 shelves, same thickness as right side, and line them up!!

yes, the glass door with black metal is ready but i haven't been able to pick it up, see picture attached, and what do you think about a sconce light at the top of the shelves? and yes the render is not showing the correct place of the shelves there are not going to be spaced like that, thanks so so much for your input, i will post a picture once its all done. Thanks

By the way can you please tell me if I do black venetian plaster for my range hood is ok?

The door is GLASS. Match the adjacent shelves in thickness, please and line up. No to the black hood, please. A little black goes a very long way.

Thanks for all the comments, Ok so I will do the range hood in a light almost like the color of the Tah Mahal in venetian marmorino matte (beige). and fix the shelves once I install the metal and glass door. and I will install some sconces like the ones in this picture

or this

The sconces in the top image are atmospheric lighting - they add a little light to the ceiling and overall to the space. The sconces in the lower image are more like task lighting - they illuminate the work surface below. From what I can see you would benefit greatly from task lighting.