Some company used to make a stain in a container which included an application tool on top. (It looked like a container of liquid shoe polish.) Perhaps it’s still available

The idea was that you could apply the product to a bit of tile and grout and then wipe it off of the tile before it dried.

You could do the same thing with an artist’s brush and some water-based paint. Thin the paint with some water. You’ll have to play around with the ratio of water to paint. (Too much water and the paint won’t hide the grout’s color; too little water and the paint won’t flow very well.)

I like the darker grout, personally!

Wow, ok thank you all! I appreciate the kind words. Guess I have to get over the fact the builder messed up but it still looks nice

I like it. Just enough definition of the tiles and pulls in your counters. I don't think you could have gone much lighter without it looking like a boring white blob. Example: I think this one below is too plain.