Google "backsplash large square diagonal white". Stick with simple, simple, simple.

If you are planning a white tile, you just need to make sure all the white work together; it's a matter of getting all your materials and verifying.

You don't mention what the flooring is, but unless you're in love with grey maybe consider a wood tone for the island that compliments the carmel shade to add warmth. As mentioned, selecting the backsplash comes last after cabinets/counter so you can see samples in your lighting and space.

We have classic 90’s 3/4” oak thin plank. And you’re right, I don’t love grey, I love all things warm. Thank you!

Put the deep gray counter top on the PERIMETER counter, but the bold stone on the ( Gray? ) island. If your kitchen has turns in the perimeter be very wary !!! of that bold veining ON a perimeter.

You have a buggy in front of a horse on a back splash.

You should post your layout......more important than all above and ideally should be much considered with any bold stone

Using that stone on the perimeter will require careful layout on each slab before you make the purchase. Take pictures of the available slabs and find a way to determine how they can be used. This has to be set in stone in your communication with the fabricator. I'd verify before he cuts, and I'd verify before letting him deliver. Good luck.

When answerin questions please use the same name you did to post the first time. I agree a very busy stone (awesome() but busy so seeing the layourt of the kitchen is imporatnt and backsplash and wall color last 2 things to decide . So deal with the counter since it will be a big issue if you have corners in your layout so the advice about a simple counter for the perimeter and that for the island is often a very good idea.I would aslo not do a different color for the island and mybe think that color for teh backsplash tile with matching grout .