It might be a good idea to purge your system of the AUR package(s) before doing anything else.
sudo pacman -Rns qt-virt-manager
Then install virt-manager from the official repo, as @Yochanan suggests:
sudo pacman -S virt-manager
Regards.
As the OP appears to have moved on to another topic without any consideration for summarising this one, let’s give it some early closure.