Your counters should definitely be the hero in the kitchen. Hold off choosing backsplash tile until your countertops are in & your cabinets are up. Make sure all lighting is LED 4000k - including the undercab lights!!!! and then your best bet is to choose a tile (IMO, simple subway in staggered brick = timeless) & grout that BEST matches your cabinets - your eye will read cabinets & backsplash as "one" allowing the countertops to be the hero.

I'm leaning in that direction. The recessed lights will likely be 5000k. I know that sounds very white but there are solatube skylights in the room so I want the lights to match the sunlight. There will be a couple of pretty pendant lights over the island (on a separate switch from the recessed light). As for the subway tile, if I can find one that is not quite simple (maybe a slight gradient or a light texture) I may be able to convince my husband. We both really don't like the basic subway. Reminds us too much of walking through subway tunnels in Boston smelling the urine in the winter from the homeless that slept there. Yeah, I know, pretty gross but we both have that memory.

It probably doesn't matter but here's the layout of the kitchen. The only place the backsplash will go is on the wall where the sink is. So it's not very much. Ignore all the colors in the picture. I never could figure out how to model that correctly, lol.

I immediately thought copper assuming those are coppery lines in the slab. While I purchased a house that has those classic white subway tiles, I think they are rather unimaginative and safe.

@HU-996389822 we did think of copper because it would go nicely with the quartzite. But I'm afraid it might draw too much attention to the backsplash. The counter is really busy so I don't want to go overboard. I have been looking at copper knobs and pulls however! Ultimately my challenge may be - which products can I actually get? So much is on back order or unavailable at the moment. So I hope to have several options chosen and hopefully will be able to get one of them.

Stunning countertop!

I like the hand-made tiles from Complete Tile. They are made in upstate NY. I think these colors would work with your warm white cabinets and the slab. They also have whites that might match your cabinets. The grout color should be close to the color of the tile to reduce the pattern. They come in various shapes and sizes, although I would stick to the subway shape.

(not a pro) Gorgeous stone! I'm glad you're planning on something very subtle, and I second the comment to wait until the counters are installed before picking a tile. Since your DH doesn't like subway, would you consider a simple square tile, e.g. 4x4? I personally like them stacked rather than offset, and it seems a pale color in a matte finish would let the counters shine.

Maybe something like this? https://www.tilebar.com/angela-harris-dunmore-tirreno-d-cor-8x8-ceramic-tile.html