If you want to create a manual backup of Joomla, you certainly have to provide a relatively large effort. But if you observe all the important points, a manual backup is also the safest variant. On the one hand, you need a secure connection to your web space, in the best case via SFTP to save all folders and files on the server. On the other hand, you should also take a backup of the Joomla database so that you know that all the text contents, configurations and user data are safe.
Backup Joomla folders and files to web space
The easiest way to perform a manual backup of your web space is establish an (S)FTP connection in the usual way and then copy the files and folders by drag and drop in the desired storage directory. You can also select the files in most FTP clients, like FileZilla used here, and Download via the menu option of the same name: