What is the opinion of Reddit about the
Italian Keyboard Sticker with Yellow Lettering Transparent Background for Desktop, Laptop and Notebook?

As far as I know, it shouldn’t be.

The stickers are just stickers you place on each key. You might want to use another keyboard for visual guidance.

You can check out an example on Amazon. In this case, you’ll still see the old letters, too, but hopefully that wouldn’t be too big a distraction.

As for changing layout in the OS, your layout should already be what you need. When you plug in the keyboard it should just use the layout defined by the OS.

All my keyboards have been QWERTY (English US), but I also use a Russian keyboard layout (done in the OS), and it’s never a problem.