Change the floor tiles whiter tone keep the vanity gray.
Can the vanity color match the floor.
I would stay away from gray.
A vanity that closely matches the floor in color creates fluidity in the space whereas a vanity that contrasts the floor can bring the eyes upward to land on wall mirrors or windows.
A vanity and the hardwood floors it overlooks do not need to match.
If you use lighter colors the room looks bigger and you can match more colors with it.
In your case if you want to go dark with the floor you should make sure you re going to go light on the walls to offset the dark colors.
You can use the same tile for the floor and shower wall if desired porcelain only then.
For the floor porcelain or ceramic pei rating 4 or 5 commercial stength will work fine.
Add a deco border in the shower that has some of the same colors as the vanity top to help pull the area together.
Brown tan and taupe bathroom.
Remember you are going to have this a long time.
The espresso is easier to match and cover if it gets.
If it is okay to keep both gray i m perfectly okay with it.
You can colour your vanity similar to the floor tile or feature wall to match it warm coloured vanities in timber coloured hues work very well with single tone tile colours that are cooler such as greys or whites.
Dark brown wood vanity light brown patterned sink and floor tilings and tan wall painting.
I m conflicted now about keeping the floor tiles gray with gray vanity.
If the bright walls are too much for you then pick a neural to match the floor and add the color as an accent in the rug shower curtain and picture.
Light tan color on the flooring tiles and patterns while the brown wood vanities sit against the greenish brown wall.
Shower and vanity top is antique white marble.
A rustic inspired bathroom.
I m considering two options.
However when they border on looking awkward together figuring out how to decorate around the clash.
Color though is a must.
Keep the gray floor tile and go for chocolate brown vanity.
The dark colors can create the illusion that the room shrunk.
You can do more with the espresso.
An old fashioned bathroom style colored with brown highlights.
For the shower walls porcelain.