Kensington sd3500v not working Big Sur

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I'm resurrecting an old Mac, and the latest OS it will run is Big Sur. I upgraded it from El Capitan, and the device was working perfectly.

I've installed the new DisplayLink Manager for Big Sur, but the message says there's not DisplayLink adapters.

What software am I missing?

I tried to download from Kensington directly, but then the DisplayLink Manager said old version detected, and should be uninstalled.

I'm a bit stuck right now, because it's an old 11" Air, and I'd like to have more screens.

The device is detected as a USB hub, but that's all.

Thanks!