since you have such a busy floor, I'd prob do a soft white or a light taupe/grayish, larger subway tile. (3x12, 4x12, 2.5X10)

I like the bottom pic of tile in the same stacked layout. it's Bedrosians Makoto tile in Tatami beige. The tiles on the right are some other colors

https://www.bedrosians.com/en/product/detail/makoto-tile

I'd also bring in the wood shelves in this color over the toilet w/some colorful art pieces or greenery.

one of these rugs w/some matching towels

do a more modern tub. some you could do a deck surround.

Here are some pics of the Makoto tiles in diff colors

both of these are the Shoji White color

Has that semi matte texture you could do a diff design for the niche

the tiles in the first two pics would be the size I'd use

Thanks for the info. I tried the same tile as 4th one from the bottom. It was nice but very similar to the wall color, so then I was thinking white.

you could do white. just not a stark white. you could even do a warmer gray color/silver.

try this shoji white

https://www.bedrosians.com/en/product/detail/makoto-tile/?itemNo=DECMAKSHW2510M

do you like the Makoto? I'd get some samples of the Shoji white, Kumo gray and the Tatami beige.

They also carry this other off white tile that might work.

https://www.bedrosians.com/en/product/detail/sorrento-tile

Comes in a larger 3x16" size too.

If you did the plain white tile, and are doing a niche, I think this Pumice color penny round would look nice in the niche.

the tile above and this one look nice w/your floor tile

The Iron color is a nice contrast and plats well w/the floor tile

This is a 2.5X9 tile called Zenia. shown in the Solar and Umbra colors

https://www.bedrosians.com/en/product/detail/zenia-tile

you could do something like this layout for the niche.

or like this, but use the accent tile on the back.

if you have the niche space, this looks really good

Here is a collection of their brown/tan/beige tile options

https://www.bedrosians.com/en/product/list/shower-tile

New tile called Sahara in diff colors that might work

I'd also do the wood shelves over the toilet w/along w/ color in some art.

How do you think the Chloe tile would look in white?