buster: https://cloud.debian.org/images/cloud/buster-backports/latest/debian-10-backports-generic-amd64.qcow2 
bullseye: https://cloud.debian.org/images/cloud/bullseye-backports/latest/debian-11-backports-generic-amd64.qcow2
bookworm: https://cloud.debian.org/images/cloud/bookworm/latest/debian-12-generic-amd64.qcow2