If we read the press release carefully:
New Onkyo TX-RZ30 9.2 Channel A/V Receiver is Technology Packed for the Immersive Home Theater of Your Dreams - Onkyo® is pleased to announce the Onkyo TX-RZ30 Channel A/V Receiver, as it expands its premium RZ Series lineup.
www.theabsolutesound.com
The odds of both subwoofer outputs being independent on this model are very, very high. The confusion around the RZ50 is simply down to the fact that the RZ30 is a 2024 model and the RZ50 is a 2021 model. No different then comparing an X6700H with 2 sub outs to an X3800H with 4, when they were both on the market at the same time.
It's a shame it's only Roon Tested. Aside from that, it's an impressive feature set for the price.