I would replace the dark worktop for a white one, if you need a refreshing look as no light bounces on dark worktops, hence why yours looks so cramped. then you add a white splashback too, subway white tiles are the cheapest of tiles and glossy ones bounce off the light great, which creates a more airy kitchen.. If you go for mirror splashback, unless you have OCD and enjoy cleaning 3 times a day, then forget it. it will always look smudged.

At Lusso Stone we now offer splashbacks/ up-stands to clients with freestanding basins, we think this can help towards protecting paintwork ( if tiles are unavailable ). It seems to be working quite well as the stone resin material up-stand compliments the stone basins whilst making sure paint work stays well away from waster marks.

I’d do differently. I’d tile up to the top of the units making a straight line, that way would feel nice to the eye, with a good flow feeling. To add to the look, the shelf will have a lovely background when you are setting your plants, herbs or spices… . I’d actually install tiles in a light colour with mate finish.

I agree with Daisy something lighter. I like number 4.