An option

I wonder about a high impact wall paper that has all the tones - sometimes that can bring them together

I picked up some really helpful color advice from one of the pros (maybe Diana Biers?) on someone else's thread many months ago. You make a color pop when you add it's complementary color. You make it recede when you keep everything around it in the same color family. The blue and green accents I put in to "soften" my own terrible 2000s-tiled "Tuscan" bathroom were making everything worse. Pulling the blue stuff out and keeping all items to neutral white & wood tones has tamed it. For your bathroom, maybe keep everything white or taupe, but make sure it's a warm white that harmonizes with the Traertine.

if you intend to remodel down the road, why not do something really bold, get it out of your system and learn what you really want WHEN you do remodel.

I once painted my kitchen Aubergine... I had harvest gold appliances and matching formica countertops. It was fun, while it lasted. I painted everything bright white when I remodeled.

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The existing white is not warm enough, but I'm afraid if you warm it up the vanity will be the standout, and not in a good way. My first instinct was to do something very dark similar to what Beverly shows. If you do that, be sure not to lean blue as that will emphasize the undertones you don't like. The only real solution is to replace the tile. Depending on how long you have to wait to do that, I don't know if I would bother painting at all since you have a challenging situation here. But if you DIY you're only out your time and a small expense for painting since it's a small area. I'm just afraid you'll have to sample many colors before you get to something you'll like.

Thank you for so many great suggestions. I do really love the idea of some bold wallpaper. As someone mentioned it might be nice to do something bold especially since I won’t have it for too long.

Bev and and Beth have some nice options

Not loving the blue

or

My be white trim

or gray

I like that black mocha for the wainscoting and the adobe sand for the walls.

I've always loved a wide strip with that tile. Not sure these are the colors but but I do like the look and you can paint it in so less expensive than wallpaper. I'd make the wainscoting the same color as the walls.

I like that idea and agree. The wainscoting should blend better it’s too stark. I bought the house this way. I’m guessing that it once had wallpaper. The other bathrooms do.

If you like the wide stripes, and I think that's a good idea, get a wallpaper. Painting them yourself is going to be a big PITA, and could look awful unless you are meticulous in getting the lines straight.

I would find a wall paper for above the wainscoting that encompasses all the colors in the room. white, black and the flooring color.

I commented above but the more I look at the bath, the more I think that adding black as a neutral will help the white and creams play together better - I'd be tempted to paint the wainscoting black so it's neither the floor color or the cab color, and then use dramatic wallpaper above with (black background)

Thanks for your input. That’s what I was thinking. I’m going to paint the wainscoting tricorn black or iron ore and then maybe try to find a reasonable wall paper in white black and cream. Maybe something I wouldn’t normally use because I will probably do a full remodel next year. I just have other projects that are more important.