I am using WordPress on my live server which only uses SFTP using an SSH key.
I want to install and upgrade plugins, but it appears that you are required to enter your FTP login to install the plugins. Is there a way to install and upgrade plugins by manually uploading the files instead of having WordPress handle the entire process?
WordPress installs and updates plugins and themes just fine if the ownership and permissions are setup correctly. However, when you upload via SFTP, they’re owned by root and cannot be updated easily. You’ll need to change ownership, either via the File Manager, or the command line.
It’s actually covered here:
Or, yes, you could download all the updates from WordPress.org and do it manually. But that’s tedious. Just fix ownership.