> and who surely all have the 'Use F1, F2 keys as standard function keys' set.
I develop for several different platforms on macOS, and have never felt the need to enable that setting, because I've never encountered any macOS software that required the Fn keys in this particular non-idiomatic way. Even macOS IDEs stay away, tending to map things to complex key-chords instead.
I guess it's a matter of taste whether you converge your familiar environment around the OS or your primary tools. I tend to do the latter (keeping IntelliJ, emacs, Chrome & shell use more-or-less consistent across platforms). I have more faith in my ongoing relationship with those tools than with a particular OS.
I develop for several different platforms on macOS, and have never felt the need to enable that setting, because I've never encountered any macOS software that required the Fn keys in this particular non-idiomatic way. Even macOS IDEs stay away, tending to map things to complex key-chords instead.