“old” udev – rules is activated a lot later than systemd-udev?

I have a machine that use both systemd-udev and some old udev rules (/etc/udev/rules.d).
One of the rules rename a specific network interface to something more readable and easy to remember.

So, during boot I saw that another systemd-service needed this network interface name that I renamed in the udev-rule.
During boot the systemd-udev is executed in a couple of seconds (lest say 4 seconds), but the renaming (etc-udev) did not happen until after 18-20 seconds.
During this time the other service did execute and failed due to the “missing” network.

I’ve been searching the net for information about the systemd boot sequence, and when in this process the old udev is added to the system. It is impossible to find this information!

Can someone help me with what service to look for, or what target to aim for with my other service to be sure that the udevs have been added to the running system?

OS: Centos8