Locale emulator was also not working for me, though that may be update related. Running Windows 11 doesn't help either I'm sure. Such a terrible OS.Did not help. Whats even more weird is that warning language did not change (same broken encoding) while system language was set to jp.
That all said, what did help is to turn the system locale to Japanese, and make sure the beta for unicode UTF-8 is unchecked. That checkbox was what did it for me. (Settings->Time and Language->Administrative Language Settings->Change System Locale)