Setup Automatic Updates on a personal LAMP machine

I’m confused on how to get Automatic Updates working on my personal LAMP machine -> fliano.duckdns.org.

Clicking “Update Now” takes me to a page that wants access to my web server and FTP Username and Password. I run an Apache server and self host using duckdns.org.

How is this supposed to work? I know I can download and upgrade WordPress manually but I’d like to enable Automatic Updates so my wife can do her own upgrades without involving me.

She only has an account in WordPress (as an Admin) but no Linux account.

What Hostname should I use? Neither localhost nor fliano.duckdns.org work … and I’m using my Linux user name and password as the FTP Username and Password.

Are there any tutorials for someone running their own complete setup?