What’s more, when I try to download something with Pamac from the AUR, it fails. But if I run it in Konsole (not on the Add/Remove Software GUI) it works.
Give relevant information then so people wouldn’t rely on their crystal ball to make guesses.
“It fails” what does that mean, is there an error message? What is the console output in the GUI (click the icon at bottom right corner when building an AUR package)?
What do you run in Konsole? what is the exact output of what you run in Konsole?
Also if you can not download this file from the computer https://aur.archlinux.org/packages-meta-ext-v1.json.gz the AUR database download can not work, fix it first if you can not download this file manually, as Pamac will also probably not be able to.