wrote

I bought a house with a nice outdoor, flat stone tiled walk way.
Unfortunately the tiler/installer was "quite sloppy" in a few areas.
There many of the tiles now have a thin, but annoyingly Noticeble
coating "film" of concrete grout on the top.

I have tried coarse steel wool, with limited (slow) improvement. Is
there a better/ recommended way, to remove that concrete film?

Yeah, you use hydrochloric acid also called muriatic acid.
That's whats used to clean mortar off the face of new brickwork.
https://www.wikihow.com/Clean-Mortar-Off-Bricks

I would really like all tiles to be fully visible, no film.