Windows does "choke" on UTF-X strings, sadly. See https://en.cppreference.com/w/cpp/filesystem/path/path for an example, paths p3 and p4 go *ka-blooie!* when executed. Though the example compiles without even a whimper.
Maybe it is an artifact of using Visual Studio. I'm too lazy to try another compiler/IDE on my Win development machine to test this.