I think I'd go with lt gray paint and a white vanity!

Lots of ways to go here. First decide your design preferences....are you going for calm, coastal, dramatic, or monochromatic?

Me, personally....I'd paint walls a turquoise ( love that with gray)... Vanity black or white. Countertop marble or marble look quartz.

I like your tile - what color grout did you use and what tile?

I would say a white vanity with marble/marble looking counter top.

As far as paint color - what is vibe/style in rest of your house?

White vanity & marble top
Or
Dark chocolate vanity & brown and grey granite

So many options......

Beachily read my mind. Color!