I followed the docs for https://docs.fedoraproject.org/en-US/fedora-coreos/os-extensions/
and of course hit a race between network-online.target and actually being able to fetch the repos.

The idea of network-wait would be:

For each configured ostree remote and each enabled yum repository, wait until we can reach those over the network.

We could add rpm-ostree install -N to network-wait. It's actually kind of tempting to make it the default...

See also https://gitlab.gnome.org/GNOME/glib/-/blob/main/gio/gnetworkmonitor.h which would be good to use for this.

This also strongly relates to #3041 (comment)

Also zincati could (should) use this instead of polling.