That marble is a very large and noisy pattern for a smallish bathroom. I would definitely live with it several months before deciding to repeat it. I would consider doing a much calmer primary bathroom. If it's important to you to have the two bathrooms relate to each other, consider using that floor tile, or a large-format marble tile with quieter veining, but white wall tile. Use the same vanity and same plumbing fixtures. The large mirror spanning the vanity and toilet looks pretty odd. You could replace that mirror with a small one sized for the vanity, and use the same mirror in the new primary bath as well.

Why on earth must they match? I would make them complementary . I don't understand unless they can be viewed from a hallway at the same time? Agree it's busy/too much drama in a small bath. Especially in a very faux marble and absolutely made busier yet, .... with matte black plumbing. I'm a no on that tile. sorry. Truly, even the look feels dated by nearly a decade.

Matching and " but also want it to be slightly different and not identical" are not the same. What you want is called complimentary or cooridinating. Anyone can MATCH what already is there--just take pictures and go shopping!

IMO a master bath is done to coordinate with the master bedroom and no reason to match any other bathroom ever .

They don't need to match in any way, but you want to keep the overall style of the house in mind. Design wise, you don't need to use any marble-look tile at all in your new bathroom, unless you want to.

I am going to guess that the bathroom you show, does not complement the style of the house. Too much tile, unless the house is very contemporary and has a lot of tile everywhere. Also the vanity seems to be too close to the tub/shower and will get water damage if you don't make sure that no water leaks out past the shower curtain.

That tile is much too busy for a small bath as others have said.. I would consider a much softer version of that just in the tub with a different floor tile and no tile on the walls. Find a pretty paint color that softens the bathroom. The current bathroom feels a bit cold and hard. You can complement without matching and do much better.

Create a bathroom from scratch that you love and tweak it to compliment what is already there. No need to copy a design that someone else create unless you really love it.

Do you have pics of bathrooms you like? What is your inspiration or style? Do you have pics of your bedroom and bedroom furniture?

Use this small bathroom for a few weeks, exclusively, and see what you do and don’t like about it.

Not only do my bathrooms not match each other, my primary ensuite does not complement my primary bedroom. It never occurred to me that it should! I knew I wanted a little jewel box of a bathroom, and I knew I wanted my bedroom to lean minimalist in appearance. So I did what I wanted.

I suppose my bathrooms complement each other in a way. They were both designed to recall bathroom designs of the first half of the 20th century, especially in the tiling. You can see what I mean at these links:

Guest Bath

Primary Bath

I am not suggesting you model your bathroom on either of mine! Mine don't seem to suit your taste at all. I'm just using my pictures to illustrate what I mean by complementing each other "in a way."

Everyone above has given you solid advice, each from their own point of view. If I were to offer advice it would be closer to that of chispa and Kendrah. And I think they've covered it pretty well, so I'll leave it at that.