Getting Agilent USB GBIP Adapter to work with NI-Visa or R&S GBIP over USB with Agilent Visa
Who would think the solution is so simple.

Agilent Visa DOES seem to support the Rohde &amp; Schwarz SMW box via USB (they just lead one to think one needs the NI VISA).

So kick away NI Visa, and have only Agilent/Keysight Visa installed.
In MATLAB, all that has to be done is to replace

visa(ni, 'USB::0x0AAD::0x0092::101165::INSTR')


with

visa('agilent', 'USB::0x0AAD::0x0092::101165::INSTR')