Those links might work. I downloaded Catalina the other day from the App Store. When it completes downloading, it starts the installer, so you have to CMD-Q to stop it. After that, it will be available in your Applications folder as Install macOS Catalina.app.
Please let us know if the links you posted work. I would like to get a full installer for Mojave. I don't think it's available through the App Store anymore.