Remote connection for nas

Hi everyone, I recently bought an ex2 ultra, but honestly I don’t have much experience with nas.
In practice I can’t understand how it is possible to download and upload files remotely, as os5 only allows you to download a file and not folders (if not the whole one)
so I tried to setup ftp, but I don’t know how safe it is, and in my opinion there must be another way to access it remotely, maybe even internally from Macos or windows.
Can you help me?
Thank you

Gee; you figured out that not being able to download folders via the OS5 app is a flaw? and it took you a week?

The WD software team has been at it for 3 years and STILL not figured it out.

FTP is not terribly secure - - - the I have done this type of work in the past is to establish a VPN connection into my home network. From there, the PC Is essentially on the home network.

To establish a VPN link, you need a VPN server on your network; and VPN client software on your PC. My router actually supports OpenVPN - and that is what I use. Others use a Rasberry PI for the server.