KDE Connect is an android app that allows you to control some parts of your PC from your phone if you have a corresponding app installed on your computer, not a file manager.
And vice versa - you can run commands on your computer from your phone. Handy when you're in bed but remember that you forgot to turn the computer off.
Well, that is what I said if you read it again ("control some parts of your PC from your phone"). I did forget about controlling your phone from your computer though, which can also be done.