There are standalone tools that offer secure FTP (SFTP) access to remote hosts like WinSCP, which uses dual panes like xplorer² to compare local with remote files, copy and delete, and do all the normal file operations. Although this works, WinSCP is a different program with its own file selection modes and workflows which one needs to learn from scratch. Wouldn't it be nicer to use your familiar xplorer² GUI to do remote file management?
For a long time I waited for somebody to develop a shell namespace extension for secure FTP, which would be usable with windows explorer and xplorer². An old candidate was an open source project called Swish, which kind of works but it is not finished and was sadly abandoned long time ago. By a lucky accident I stumbled on a comment talking about WinFSP, which is the answer to our secure prayers!
There are a number of free and paid SFTP solutions listed here
These 2 tools allow to map a remote server as a drive letter securely. The path of the remote connection starts with \\sshfs\ followed by the username and the server address separated by @ (similar to FTP "paths") e.g.
To attach the drive, right click on ThisPC icon and find Map network drive menu command. Pick a drive letter and supply your SFTP path in the dialog box as such: (you will be asked for your password when you click Finish button)
With WinFSP device driver plumbing in place, the procedure is identical to mapping any network drive, and then you get a filesystem object like Z:\ that any program can use to securely access the remote files, including xplorer². The only indication that you are actually using SFTP will be a slight sluggishness when you browse the mapped drive Z; other than that you can compare, preview, search, transfer files, and in general have all file management mod cons!
When you are done, right click on the mapped drive icon and pick Disconnect menu command to terminate the session.
ps. To make this SFTP work with xplorer² you need the latest build 5.201