You have so many pretty vanity colors in your ideabook! I would pick a shower curtain I love first and paint the vanity to complement it. Since the space is small and I don’t see a window, I would keep the walls white. I think that’s what you are saying you want to do. Maybe even a white shower curtain with a colored trim? This one is from Serena and Lily, but if you sew, you could buy a plain white one and add any trim you like:

Thanks for the shower curtain idea. Yes I want to keep the walls light, no window & small room.

I’m not an expert in white paint colors for the walls. I’ve gone down many rabbit holes trying to figure it out! But if you search Houzz for “White paint color to go with quartz carrera marble countertop” you will most likely find a number of threads with suggestions.

I just did a search out of curiosity. Many threads! It would help to spell “Carrara” correctly, lol. I had to google the spelling ;-)

A lot of suggestions for whites. Are you changing your lighting? You should at least get some 3500-4000 K LED bulbs. Dimmable is nice if possible. Do that before testing paint colors. The color will look very different depending on your lighting.