Vostro 5000, Wake on LAN not working (s4/s5)

Brand new machine / setting it up - cannot get WOL to work from power off.

I have done this with prior generation of Vostro desktop without issue and I know I'm sending proper WOL signal over LAN (because it will wake it from sleep S3 state), and have double and triple-checked all the BIOS settings, still can't get it to work.

Unlike most PCs I've seen, when this machine goes Power Off, the wired ethernet adapter LEDs go off and the Power Supply's LED also goes out, which leads me to believe despite the BIOS settings to allow WOL, Dell has the BIOS set so that power off disables everything...?

Vostro Model 5090   Bios Version 1.2.0

(The BIOS was updated with critical update from Dell during initial setup steps.)

Update: 12Dec19 - have not heard anything but virtual assistant msgs from Dell asking for product info & saying I'd be contacted, but hasn't happened. But, I have done further diagnosis/troubleshooting:

The Power LED on the power supply (back) does go out in S5 & S4.and Wake-On-LAN does not work (the LEDs on the built-in ethernet adapter extinguish in these sleep states).

The Power LED on the power supply (back) also goes out in Standby S3, and Wake-on-LAN does work - the LEDs on the built-in ethernet adapter are active in S3.

This behavior is out-of-the-box without updating BIOS/firmware as well as with the latest updates. (Lucky I have 2 machines to set up, and while I was doing WOL towards the end on the first, I hadn't touched the 2nd machine so able to start from the cleanest of clean installs.)

I think someone messed up on this motherboard/firmware....