Forgot to mention I found the AirSpy HF repo on github: https://github.com/airspy/airspyhf
These tools work with the Airspy HF+ Discovery on the Pi and Mac, (although I did still need a windows box to update the firmware). They're also not yet packaged on Debian, or in the official homebrew project.
I've not had much time to play, but I think airspyhf_rx should work a lot like the RTL tools.
Also, this blog has a lot of cool content, even though I can't read it: spinorlab.matrix.jp/ja/page/3/
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