@mrXYZ
Unless you're doing something very unusual, you're not going to end up with many AUR packages. I've run Arch on SBCs without much trouble.
There are severely steps in between Gnome/KDE and Awesome. XFCE and Enlightenment are more user friendly options that are still quite lightweight.
@Dirk @Fungus
@Lazylazycat
You can do what's called "dual boot" where both (or even more than 2) OSes are available and you pick which to use at boot.
@Anarch157a