unified cgroups / rootless podman

[Csepp]

I'm trying to set up a Debian container to test some things and thought
I'd try rootless podman instead of a simple chroot which requires root
privileges.
TLDR I ran into some problems which on other distros are apparently
solved by configuring the init system.
>From the StackOverflow answer:
> From what I see, you need to set rc_cgroup_mode="unified" in the rc.conf file.
> If you were using systemd instead, you'd need to run # grubby
> --update-kernel=ALL --args="systemd.unified_cgroup_hierarchy=1".

What - if anything - is the equivalent on Guix/Shepherd?