I use one of the new MacPros - all Thunderbolt 3 / USB-C for all ports, and it's working fine with my HackRF, RSPDx, and for programming my USDS-100. I also have some cheap RTL-SDR devices for dump1090 that work through USB A->C adaptors....no issues with anything. Even the RSPDx which only comes with a bizarre USB connector is just fine going from their USB-2 Type B into a USB A hub into a USB-C port on the computer is working like a charm.
Like a lot of things, it may depend on the quality of the cable and adaptor you are using. There are some really dodgy ones out there, no doubt.