Apple does not have an API for either FTPS or SFTP, although on macOS you may be able to make some headway by invoking the sftp command-line tool.
I did get the command line running with Runncommand using the keygen password-free method, but in this case I need to sign into a server that I do not have the ssh key for and pass along the password to sftp. And, I read that it is frowned upon to be sending text passwords on the command line.
I suppose I can use the TProcess method for sending the password when asked.