Happy Update: After Joseph didn't respond to my PM, I called GranQuartz in Seattle, again. I figured if I was willing to pay for a flight and expenses for two, I could certainly offer a generous trip charge. Turns out, they lost my number and did have someone! He came and used the Quartz Renew. It was an all day job with all the taping to protect cabinets, etc and the fact that I did have more than one dull area from using BarKeep's Friend (which the original installers said to use). I've attached a picture of the same area as the one above in a previous post 8 months ago which showed one of the spots. I cannot see the previous spot at all! Quartz Renew really did the trick. (Any variation you see, like browner areas, is an artifact of the light. The countertop now looks very uniform.)

I have strange, irregular marks that do not appear to be hard water stains. They also do not align with the markings. They have been there since the countertop was installed, but now it seems they are more pronounced. They basically look like the countertop us dirty. It's only on one particular slab. They appear different than the pics in other posts. Any suggestions how to remedy this? I'm getting ready to sell.

Yes, @Fori, that's what I said to my husband about the molding there--he's a bit of a perfectionist!! I was like, you don't need that there! But he can be a little obsessive about some things! I will pull out the range later and look at the space for that pipe. In figure 3 it looks more centered than to the right where we have it. We'll have to see what we can do about it. Better yet, I will just pull it all out and redesign it. No worries. Lots of time during COVID. Thank you for letting me know @JuneKnow. Although, it's such a little space, not much can be redesigned as there are only the two walls! Better yet @JuneKnow, I can just leave the backsplash until it scorches too--then pull it all down and put up something else. No different than pulling it down now. Same money and time. :)

This looks so ugly and breaks our heart after spending thousands of dollars on the slab and labor. The GC says that is not a big deal and we can just add another piece of trim. He says that most times walls are not straight and trims hide it. To me it seem unacceptable as there should not be a trim in the first place and the backsplash should be the thing hiding any gaps. The trim solution looks ugly. Your enemy here is the concept of perfection ... and Pinterest. Saying they have "ruined thousands of dollars" of materials is going overboard, making a catastrophe of something minor. This is not a horrible thing, and once the kitchen is finished and filled with all the accessories, you won't see this like you do today. I cook every day and I bake, I deep fry, I broil. There is no sign of heat damage to the Formica after 50 years of use. We all know that Formica is plastic and not exceptionally heat resistant. Eh, look at these two pictures, taken from this thread ... what difference do you see? The second stove has a back, which protects the formica from the worst of the heat. That can make a big difference in whether the backsplash becomes discolored. Believe it or not, laminate tops are a lot more durable than people give them credit for. Folks had them in their homes for many years. Eh, I think maybe it used to be better than it is now. When we moved into this house 20 years ago we had the original laminate /formica ... the pattern was hideous, and some of the edges were torn off, but the main work spaces were in perfect condition ... and it was over 30 years old. We replaced it with new laminate (because the kitchen is huge, and it's what we could afford then), and it is now badly scratched up ... you'd think we use knives directly on it.