I do not ask! I will help… How to type \ on a windows keyboard on mac:
Shift+alt gr+7
You are all set!
Mac mini, macOS 15.2
What language keyboard are you using? All English keyboards, mac or windows, have \ printed right on a key over at the right side. And option shift 7 produces ‡ . So it's not clear whom you might be helping. Someone with a German keyboard perhaps?