Depends on the style of the bathroom. Pale lavender can be perfect with mint green. Or terrible.

Do you have a picture of the bathroom as it is now?

Charcoal / black might look striking

decorating around a peach colored tub------photos

Like indigo blue or charcoal, instead of black, will give you same dramatic effect. Like a lavender or mauvey pink. Peach is supposed to be a color flattering to human flesh but I wouldn’t use it in this bathroom, unless you go white w/a drop of peach or orange.

You should post a picture if you are looking for a decent advise. You could go with contrast colors or all white - really depends on what the bathroom looks like now.