Not sure about the network issues…
I was able to reproduce this issue locally and develop a fix. Details are available at Details on this week's IncusOS updates and steps for updating to the current stable release , and is fixed by Fix legacy system updates by gibmat · Pull Request #1142 · lxc/incus-os · GitHub .
You’ll need to wait for the next stable IncusOS release, then rebooting your system should be able to automatically fetch the update, apply it, reboot and you’ll be back to a fully functional system.