Clearly
this hub is the best for FRC use.
Or maybe it is
this one.
More seriously, I think you're unlikely to run into throughput issues in FRC matches if you are using one hub to connect two joysticks and a USB Ethernet adapter, even if you're running at USB 2.0 speeds. I would instead focus on getting a USB Ethernet adapter that has rock solid drivers. Finally, using only one of the USB ports on your computer means that the port lasts longer. They do wear out.
Oh, and please test it out before you get to the competition. These haven't been stocked as spares in previous years.