No quartz on the backsplash. Quartz can warp and scorch with heat. I'd pick up a few tiles in different whites, sizes, etc and play around with layout. Many tile companies will let you take out samples so that you can view in your space. You can also go to tilebar.com and purchase 5 samples for $5. Play around with geometrics as well... might be a fun route to go!

IMO you can wait for backsplash for a very long time and I honestly would not choose white I woudld choose a gray from the counters in a large format glass subway tile and I never like mixing real stone with fake it does not do either material a favor. The other option would be a large backspals in the same material as the counter.

I have a similar kitchen. We did a gray 3x12 gray backsplash. Most here will tell you that gray is on its way out. The trend will be swinging back to warmer. I happen to like gray. That said, a backsplash can easily be replaced year's down the road. But, getting back to you. A soft gray blue, or a fancier tile. You need to decide if want subtle or bold. A color, ir white?

None of those. first off, NO to the smaller sized tiles (like those sheets w/the 2x4's on them. your countertop is too busy for those smaller tiles. Plus, they just don't fit w/the style you have. The arabesque, maybe, but not any of those Here's a larger size and slightly diff shape. I also wouldn't use that bright white (BTW, have you considered doing pull instead of the knob? your doors are so tall, I think a pull would look more proportional. I mocked some in here) Slightly diff arabesque that I think would look pretty w/your stone. I believe this is from Riad Tile Since you have the warmer wood tones w/the floor and the island, I'd lean more toward slightly warmer whites and grays Here are a bunch of whites from Fireclay tile. shown next to Tilebar Harlequin in their Natrual White. Ivory glass tile from floor and decor I really like this one too. (Check Bedrosians and go through some of their tiles. they have this size, which I think is perfect for a backsplash. please, no 2x4 or 3x6 tiles!) this slightly warmer sand dollar color looks great w/your stone and your wood https://www.bedrosians.com/en/product/list/backsplashes/?f_ColorGroup=Beige%2cTan%2cWhite%2cGrey Here's another one from Tilebar. (you get5 samples for $5 over there. Or, check on home depot or wayfair under IvyHill tile. they have the same ones under a diff name) This is the 5x5 tile (which I like in the offset) in the cloe tile. cloe has a cream too 2x10 Newport tile in Hibiscus. this color may work. it's a taupe speaking of taupe: This Pearl gloss concerto is really pretty. I love it in the herringbone. take a look at this one the two bottom left are Shadebrick, and white pearl glass tile , Oceanside tile.