How to build centos 7 with fresh systemd?

I’d like to build Centos 7 with relatively fresh systemd which can run on cgroup v2 only node (like on ubuntu 24.04).

There is repo with prepared rpm - jsynacek/systemd-backports-for-centos-7 Copr

I found base config for centos 7 in lxc-ci/images/centos.yaml at main · lxc/lxc-ci · GitHub

I’ve read Use distrobuilder to create images - distrobuilder documentation and How to build images - distrobuilder documentation

And I still do not understand how to combine it to build centos with new systemd and is it possible to do it completely on cgroup v2 only node?

Are any examples how to add packages during build?

You can probably just run through this as a post-packages action, assuming the whole thing can be scripted to not need any user input.