The huge-looking sizes are not representative of actual size on disk. On first installation of one app of a kind, their runtime packages get installed as well. For example, installing GNOME apps will install the latest GNOME runtime. But after that, installing any other GNOME app takes little to no space.

In your case, you don’t seem to have any apps installed as Flatpaks, which means even the freedesktop runtimes are missing and need to be installed. That’s probably why it looks so huge.

Just use fish or setup autocompletions and suggestions on your terminal.

For anyone looking at this in the future: https://www.zoho.com/mail/help/adminconsole/catch-all-setup.html