path_provider will probably undergo some changes soon, there are some open issues:
https://github.com/flutter/flutter/issues/35783
As of right now, the best way to get the download path on an Android device is to use:
/storage/emulated/0/Download/
No (s) needed.
And to get the external dir path in Android:
/storage/emulated/0/
The “emulated” word does not mean it’s the emulator path, it’s just a naming convention.
Make sure you have permission to write to the file, add this to manifest.xml file, right under <manifest tag:
<manifest package="..." ... >
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
and also request permission at run time.