How to transfer a local backup to FTP?

Question

Backup

The server runs rsnapshot for backup, I decided to protect the server from any threats and upload the backup somewhere, I bought a disk from firstvds, although the description indicated that the backup would be done locally, apparently this is only available for vps with the ISPmanager panel, which I not using.
There is only one solution left: FTP.
How to proceed? Would it be correct to just copy all hourly, dayli, weekly backups to ftp and somehow configure rsnapshot to use ftp (is it possible at all? instructions are only for ssh on the Internet)