No matter what you have to seal that marble. Looks pretty good to me - maybe someone else can see what you’re seeing and advise more.

I think the surface of the marble has to be sealed before it's grouted, to prevent the haze from adhering. But honestly, I htink it looks pretty good too. Maybe the grout has ended up with a variegated tone? Or maybe we need to see a photo from before it was grouted to understand what you're seeing now.

I found this one. Its amazing the difference

In the photo you just posted, the install is not grouted yet. You should not be using vinegar or anything acidic on stone. Please check out what the grout supplier says to do before you do anything else; they'll likely have the right products to try.

Yes last photo was pre-grout and so called clean up.
I’ve emailed the company seeking their advice.

The original tile was laid on a Thursday, no grout. Rep came Friday to check the install and said this isn’t right, I’ll have them back out tomorrow to replace some of these around the edges. Different crew showed up Saturday morning. The edges were so uneven, some not even stuck to the mud and horrible gaps. I had a choice to live with it or have them pull the floor and redo it. They pulled the floor, paid for new tile and laid the new tiles that morning. Came back on Monday and did the grout work. Typical wipe down with water and a sponge.
I just don’t understand why the platinum colored grout has turned white.