Anyway, try asking on the systemd mailing list, which is where udev help can be found, this list really isn't alive anymore at all, sorry.
np, thx. i've posted in systemd:matrix.org; we'll see what pops up there.
Try running 'udevadm monitor' to watch the events to ensure they are what you think they are.
just to close/comment here before moving on, @ shell after boot udevadm monitor | grep enp5s0 KERNEL[40344.410195] change /devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:05.0/0000:05:00.0/net/enp5s0 (net) UDEV [40344.529849] change /devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:05.0/0000:05:00.0/net/enp5s0 (net) and, checking boot logs, journalctl -b | grep systemd-udevd | grep /etc Dec 20 19:24:16 dev systemd-udevd[522]: Trying to open "/etc/systemd/hwdb/hwdb.bin"... Dec 20 19:24:16 dev systemd-udevd[522]: Trying to open "/etc/udev/hwdb.bin"... Dec 20 19:24:16 dev systemd-udevd[522]: Reading rules file: /etc/udev/rules.d/11-dm.rules Dec 20 19:24:16 dev systemd-udevd[522]: Reading rules file: /etc/udev/rules.d/59-persistent-storage-dm.rules Dec 20 19:24:16 dev systemd-udevd[522]: Reading rules file: /etc/udev/rules.d/59-persistent-storage-md.rules Dec 20 19:24:16 dev systemd-udevd[522]: Reading rules file: /etc/udev/rules.d/59-persistent-storage.rules Dec 20 19:24:16 dev systemd-udevd[522]: Reading rules file: /etc/udev/rules.d/61-persistent-storage.rules Dec 20 19:24:16 dev systemd-udevd[522]: Reading rules file: /etc/udev/rules.d/64-lvm.rules Dec 20 19:24:16 dev systemd-udevd[522]: Reading rules file: /etc/udev/rules.d/65-md-incremental-imsm.rules seemingly missing/ignoring, ls -al /etc/udev/rules.d/ -rw-r--r-- 1 root root 2.2K Dec 20 18:47 99-enp5s0-sysctl.rules where find /usr/lib/dracut/modules.d -type f \ -iname 11-dm.rules \ -o -iname 59-persistent-storage-dm.rules \ -o -iname 59-persistent-storage-md.rules \ -o -iname 59-persistent-storage.rules \ -o -iname 61-persistent-storage.rules \ -o -iname 64-lvm.rules \ -o -iname 65-md-incremental-imsm.rules /usr/lib/dracut/modules.d/90dm/11-dm.rules /usr/lib/dracut/modules.d/90dm/59-persistent-storage-dm.rules /usr/lib/dracut/modules.d/90mdraid/59-persistent-storage-md.rules /usr/lib/dracut/modules.d/90mdraid/65-md-incremental-imsm.rules /usr/lib/dracut/modules.d/95udev-rules/59-persistent-storage.rules /usr/lib/dracut/modules.d/95udev-rules/61-persistent-storage.rules /usr/lib/dracut/modules.d/90lvm/64-lvm.rules
