I love the vanity so please do not ruin it by painting. I think maybe just a big piece of art on the large wall and walls the same color as the white in the floor.IMO any patterened wall paper will fight with that floor so at best a textured wall paper maybe. I would paint one wall black and put that art on that wall

pmoskie, it does look more blue in that photo. maybe it's your monitor or the pic you have. here's another picture of it and it looks more blue than gray. have you ordered a sample? it's listed here: https://thezhush.com/five-perfect-powder-rooms/ they said they used Mineral. and heres the link they used to order it. https://www.decoratorsbest.com/products/schumacher-oiseaux-et-fleurs-mineral-wallpaper?sscid=61k5_u9a9k Here are some other photos w/it I suppose if you used a soft blue paint color, it would bring out more of the blue tones. Just like if you were to paint the wainscot in one of these gray tones, the paper would look more gray. (Personally I'd use that blue color on the walls. It's beautiful) or, try some of these colors Mineral, Porcelain and Cinnebar and Peridot are the colors it comes in do you have a sample of the paper? why don't you order one? i do like the marble tile you've chosen.

I'm sure you don't want to know the time but perhaps the tile. I don't know the name of it. I picked it out at ProSource in Vero, FL.

In my mind your tile is killing the space you have for creativity. You could create an artistic design with the tile, like a mosaic, but that would be challenging and expensive. You can be creative with the type of wallpaper you use, for example graffiti wallpaper. But your tile design takes up most of your wall real estate. You could add creativity with unique art. At least that is transferable to other spaces. You could focus on the ceiling for creativity. Probably not with wallpaper because of the shower but it could be stenciled.