Volume HUD Status Broken
As in, it’s not going away?
Have you tried reloading Gnome? You can do that by either pressing Alt-F2 and entering “r” in the dialogue, logging off/back on, or rebooting.
Depending on what theme you’re using, yes. Some themes don’t have it.
Does sound actually work?
If so, try to see if changing DM will help, Antergos uses Lightdm by default, but the default DM for Gnome is GDM,
Just type in the terminal:
sudo pacman -S gdm
then after installation:
sudo systemctl disable lightdm && sudo systemctl enable gdm