Yes the AUR is the best feature of Arch, which is why I am still using an Arch distro and not Fedora or Debain.
However one of Manjaro's features which other Linux distros don't have, is how much of the OS's troubleshooting and repair is in GUIs. For the most part I can setup a fresh Manjaro install without touching the command line once. And that's how I want to use my machines, I want to just browse the web, play games, or do office tasks (the reason I use a computer), not trying to figure out how to install a GUI package manager from the AUR in EndeavourOS since it doesn't come with one.
I wouldn't consider Fedora or Opensuse TW better than Manjaro. Just trading one issue for another. Honestly I replaced my 1 year old Manjaro install (when I borked my DE) with Fedora.
Fedora lasted 1 month before the btfs filesystem broke and I lost all of my files with no way to recover. Ontop of the difficulty of adding community copr repos for features like XPadNeo, DNF being so slow that Discover would barley function, and being about 2 months behind software fixes for a specific graphic driver bug that prevented me from playing some UE4 game.