Decklink Mini Recorder 4K: 7.1 audio capture help?

Hello!
I recently purchased the Decklink Mini Recorder 4K because I was under the impression that it supports capture of 8-channel audio via HDMI. However, no matter what I do, Windows 11 only recognizes it as a stereo input device.

I've downloaded and configured the latest Desktop Video Setup app and updated the Decklink's firmware via USB. In the Desktop Video Setup App, the device's properties only show options for "Video Input" and "Conversions". There are no visible options for audio, and BlackMagic's manual doesn't specifically discuss the Mini Recorder 4K at all from what I can see.

As far as I've been able to find online, there aren't any other setup steps to take. Is there anything I'm missing?

Here's my system specs:
Mobo: HP 89B5
CPU: Core i3-12100, 3300 Mhz, 4 Cores
GPU: Intel UHD Graphics 730 (I had to switch to my CPU's integrated graphics to free up a PCIe slot for the Decklink)
RAM: 8gb
OS: Windows 11

In addition, here is the System Report exported via the Desktop Video Setup app:

Device Information
DeckLink Mini Recorder 4K

Persistent ID
14360413

Video Input
HDMI

1080p59.94, 8-bit BGRA

Video Options
Capture 1080p as PsF - Disabled

Device Interface
PCI

PCIe Status
Link Width: 4x
Link Speed: 5 GT/s

System Configuration

Operating System
Windows 10.0.22631

Physical Memory
8262 MiB

Physical Processors
8

Any advice would be greatly appreciated; I've been troubleshooting this issue for weeks now!