having just been searching for a "copper-less" USB fiber optic connection (precisely for this sort of antenna testing application at work): they aren't easy to come by, and are kind of expensive ($900). You'll see lots of inexpensive AOC (Active Optical Cable) USB over fiber cables, but they have a couple copper conductors to provide power to the "far" end of the cable.



Optical serial port, or optical Ethernet are *much* easier to come by.

I've used a beaglebone green wireless to get remote USB access to a device, and also a Rpi. It's kind of clunky to be sure, but it does work, because you're doing two hops - your PC/Mac to the remote processor via IP network (WiFi) and then through the device.
And you've got to get power to the processor (battery works).

Since the NanoVNA has serial access (via a couple of pads on the board) that might be the easiest way.
I'd assume you'd use some sort of program (I use NanoVNA-Saver, but there's various other apps) to control the NanoVNA, so it's not like you need to see the screen.