@HforHotel
Actually I think a PP has hit the nail on the head. It's not necessarily the grout colour that's the issue...the different tiles don't work well together. They're 2 entirely different styles. White grout would make it slightly less noticeable.
Agree.
You'll probably get used to it, but if you do change the white tiles in future I'd probably go for much, much bigger tiles (that don't correlate in size to the small ones) so the contrast between the (very beautiful) herringbone tiles and the rest of the wall is much greater and clear cut. Then it is an obvious demarcation and clear that one is a feature wall and the contrast is deliberate.
What you've done is almost the tile version of having a painted feature wall only one shade different from the other walls.
Also, with larger tiles there are fewer grout lines (of whatever colour) and it makes those walls less busy so they don't pull your eye away from the feature section. The white tiles are so small all I keep looking at is the grout lines and volume of tiles. If they were much bigger my eye would go back to your feature wall instead of going "wow that's a lot of tiles" .
I think when you're using contrast you need to be brave and really contrast. By trying to align the sizes and shapes of the two tiles I think you've lost that power.
For me, it does remind me a little of grimy public places that makes you feel a little uncomfortable and I also think there is jarring effect in that the white tiles are too small which makes it look busy and distracting as well as less like a feature wall and more like the money didn't stretch tbh.
These are just my personal impressions and experiences of experimenting with contrast myself. It doesn't look awful, but since you're not happy yourself and contemplating already then these are my thoughts!
On a positive note, I don't normally like herringbone but I think your wall looks beautiful.