This post suggests that it could be a packaging problem: https://nocthoughts.com/2023/04/26/arch-linux-virt-manager-and-firewalld.html
In any case, the libvirt-daemon-driver-network package contains template firewalld zone files in /usr/lib/firewalld/zones/ - it suffices to copy them to /etc/firewalld/zones/ and restart firewalld.
