Problem solved
Used
FBXConvertAsync::INVESALIUS_PATH = FWindowsPlatformMisc::GetEnvironmentVariable(*FString("INVESALIUS_PATH"));
FBXConvertAsync::PYTHON_FILES_PATH = FWindowsPlatformMisc::GetEnvironmentVariable(*FString("VROSCOPY_PY"));
**FWindowsPlatformMisc **instead of FGenericPlatformMisc
Didn’t know about this library until I stumbled upon an obscure page on google… (thanks to this site Is It A Drive? Is It A Directory? No, It’s… - Blog : Coconut Lizard)
Hopefully this is gonna help someone in the future