I have several physical machines that I use as libvirt hosts. And I want to automate ALL. THE. THINGS.
So, I built some tooling to do that.
Just install podman, check out the code, and execute ./run.sh -t debian (or rocky).
If you've stumbled across this from the broader interwebz, turns out there's a much easier way of doing this.
https://weldr.io/lorax/mkksiso.html
It has to be run on RHEL or a derivative (CentOS, Rocky Linux, Fedora to name a few).