Do you need warm or cool tones in the white? There is no best one...depends on wall color, trim, flooring, and counters. Photo?

I'm questioning your countertop choice. Balboa Mist and Collingswood are warm grays leaning beige/greige which seem consistent with hickory floors, but the counter seems like a cool gray. It's hard to tell what it's actually like, but I will say that the larger vein patterned quartz can be difficult to match and many complain in this forum of them looking very fake. As for a warm white, BM White Dove and Simply White are all popular warm whites, but it would be best to paint a door or something and bring it to the stone yard to check the color against your stone.

Have you contacted Diamond. Or asked Lowe’s to do so.? We just installed a factory finish color on our house and they gave us touch up paint as well the formula was readily available at Sherwin Williams . I’d go to Diamond either the local technical rep or thru email into their system technical support or customer service to get the formula . it should not be a mystery if it’s exact match you want altho I don’t know why . Often trim is differentiated by a shade or two.

My perimeter cabinets are white and my island is is a blue/gray. I selected a leathered granite called Thunder White which has cooler gray tones. Like you, I wanted a natural stone. There are granite inclusions in this stone. Personally, I love the random natural beauty of the inclusions, but others may consider them undersireable.