Here is some reading material
https://linuxconfig.org/setup-ftp-server-on-linux
Here is a excerpt from the second web site.
WARNING – FTP IS NOT ENCRYPTED
FTP will suffice for some situations, but for connections over the internet,
SFTP is recommended. This is because FTP is not secure to use over an
internet connection, since your credentials and data are transmitted without encryption.
The ‘S’ in SFTP stands for ‘Secure’ and tunnels the FTP protocol through SSH,
providing the encryption needed to establish a secure connection.
From the above:
The ‘S’ in SFTP stands for ‘Secure’ and tunnels the FTP protocol through SSH
Since this uses FTP through SSH, why not use SSH to start with?
HTH
Pudge