Your talking about something that is akin to the MATE DE where only the top (or bottom) panel would exist, yet still have the full functionality of what the Unity offers?
I would question that it might not be, though that’s just my guess. I’m saying this because Canonical makes their Unity product for themselves, not for Arch systems.
Secondly, have you looked inside
dconf-editor settings? Or the
CompizConfig Settings Manager there should/might be a tab a.k.a ‘Behaviour’ settings. Have a look there. But I think that inside that app there is or might be only the option to hide the launcher, which I know is not what your looking for, rather to have it out of the way permanently, so to speak.
If your going to use the dconf-editor, I’m not 100 percent sure, but you might need to navigate towards something along the lines of Desktop > Unity > Launcher
I don’t use Unity on Antergos but I am making a stab at helping you with it as best as I can figure out for you.
Regardless, I would try there with those two first.