You've solidified all the debris in the wire brushed texture by using a steam mop. Any prefinished floor should have been installed very near to the end of the project. But builders and contractors do things differently from one area to another.

There are methods to improve the situation, namely an article by the National Wood Flooring Association or Wood Floors Magazine, but I can't find the link. Hopefully others can locate it.

Vacuuming? Must have been from a book read only "technician"

What is the finish on the floor? Some type of polyurethane or a hard wax oil?

Were the floors covered with ram board , or anything else, to protect them?

The most dangerous people to my engineered wood floors were the painters and their sprayers. The don't seem to realize the overspray travels far beyond the areas that they have taped off.

I would ask the floor installers how to refresh the finish on your floors. Hopefully the people who sold you the floor are the same as people who installed them ... only way to remove one set of finger pointing when you have problems.