Whatever you prefer actually. AUR really might work out better. But generally you don’t need to install software from official sites on Linux and rather use Flatpak/Repo packages or AUR in case of Arch/Manjaro. This way things could be auto updated.
You always should read PKGBUILD file to check which source it uses and what it does, but tbh problems occure very rarely. In this case it just downloads official AppImage and installs it system-wide.
I’d go with Flatpak just because it’s easier to update. Pamac has a support for Flatpaks so you could use it to install this package.
I’m not into this guides, even when i double read that stuff… i always have a feeling that i getting lost
I just activated Flatpak support in Pacman (GUI) but i can’t find this game when i search under Flatpak.
And your Guide showed only to install Discover (for KDE) but ignored Pacman.
Err Pacman is GUI and Pamac is CLI right? I hope i don’t make mistakes here
Edit:
But when i type in Terminal flatpak search beyond all reason, the game is showed up.
In Pacmansearch GUI is no Pakage found. But i just activate Flatpak under Propertys from Pacman.