GNOME software requires a default route to work

I'm using GNOME Software in Fedora 38 within Qubes OS. It's a kinda special setup as the Fedora 38 is a template and doesn't have any network interface attached, dnf works by using an http proxy routed through the hypervisor to a dedicated network VM.

Reproducer

When using no default route and a dnf proxy, when looking at the program "Ardour", clicking on "install" make the button switch to "cancel" and nothing happens for hours.

pkill gnome-software
gnome-software --verbose &> gnome-software.log

gnome-software.log

I found a hack consisting of adding a dummy device with a fake route, GNOME Software started working after running the commands:

ip link add dummy0 type dummy
ip link set dummy0 up
ip addr add 192.168.0.1/24 dev dummy0
ip route add default via 192.168.0.2 dev dummy0

Another hacky solution is to attach a network device but block all the network traffic.