Can't install any plugin

Hi there,

I can't install any plugin because of the ftp settings of my hosting (google cloud). I have a dedicated user name/password and private key (ssh-rsa) in order to install other plugins through wordpress. Premissions in wp-content are 755

Unfortunately when asked for ftp credentials through WPMU DEV I couldn't see the option to add the private key.

An easy option for me would be to install directly the plugins from zip files through wordpress but it seems that this option is no longer available?

Could you please advice?

Thank you very much.