PSA for others wanting to scale up on the Pi platform, while the CPU usage is low there appears to be a limit of around 12 devices on the USB 3 ports (including any hubs you have).  So I'll have to run 2 Pi4 units to take advantage of the power savings vs. trying to run so many of these on windows (which uses tons of power / cpu and generates heat).
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is that 12 per port?  or 12 between the 2 ports?