There were no arch repo ddos, there were cases where the AUR went down because pamac was searching Aur packages as users were typing package names on it and turns out there were way too many users going into the Aur. It is actually quite sad how much disinformation there is about manjaro that even the manjarno snorlax repo recently corrected a bunch of critism it had about manjaro before being taken down lol.
Also Manjaro only ships pamac with KDE in both versions, no idea if gnome includes their store in their packages. Manjaro also includes already functional and useful versions of window managers like i3 that are already setup, if it wasn’t for it I would have never discovered how useful i3 is because setting i3 from the beginning is very difficult.