I use Arch but you are kinda over zealous about how good AUR is. It is completely unmoderated and, as others have said, a security risk. But it can also pretty easily bork your system because of a bad package. I don’t know how long you’ve been using Arch but it’s only a matter of time before you’re pulling your hair out trying to fix a broken dependency.
Arch is also not the only distro with giant repositories. Void has a pretty massive repository but it’s better moderated. The Debian universe is just as big if not bigger but you have to add repositories, it’s not as central. Same with the Red Hat world. Arch just dumps it all in to one chaotic bucket which is very convenient but there are downsides.