@fossette A passive resistor is in no way a better solution, it's still the wrong way of going about it. It was simply to confirm that OP's problem was a power-supply issue, which it was, and it's now solved. The proper way of doing it would still be a linear voltage-regulator or a small SMPS, and he did mention he is looking into a proper power-supply now.
@Tobias-Malm140 As far as I understand, the Vout pin is not a general power output, but specifically meant to power the ethernet transformers. It is switched on by the system only when the ethernet port has to be active, and is off otherwise to save power.
As we don't have the schematics of the Omega2 yet, I can't be sure - but from the datasheet of the MT7688 I would assume that Vout is connected to pin AVDD33_TX_P0.
So not seeing any voltage present on Vout is not necessarily a sign of the Omega not working, but just that it has not (yet) switched on the ethernet.
The case of @ccs-hello seems different, it appears his Omega2 actually has a part missing, so Vout is not connected physically to anything. Most likely, a ethernet expansion would not work correctly with his Omega2.