I haven't requested the source code for the NR7101. It's a MT7621 device with a Quectel modem. Didn't think there would be anything new in there.
My best guess is that we're missing something related to ethernet <-> xhci in the MT7621 SoC. Maybe there's a more efficient way we can move buffers between those IP blocks? If there is, then that should affect any MT7621 device with a USB3 port.