Yes, you can directly access it for now, but it is a mistake in most cases.
Its path is File.Combine(File.DirRootExternal, "Download").
You need to request the write external storage runtime permission.
You need to request the legacy external storage option (
https://www.b4x.com/android/forum/threads/android-jar-targetsdkversion-minsdkversion.87610/#content). This will be blocked in the not far future.