Bester installation image missing virtio net Modulen
About a year ago, Viktor Mihajovski pointed out, that the virtio net modules (and deoendencies) are missing, this is still the case.
For an installation to work via virt-install, you have to manually add failover.ko, net_failover.ko and virtio_net.ko (debian-10.9.0-s390x-netinst.iso) and set the right console (ttysclp0).
These seem like really easy additions to make things work again (adding them to the image).
I‘ll put my workaround on of those wellknown portals during the day, for anyone who is interested.