We do not certify any specific third-party USB hubs. However, we have tested various USB hubs for precisely the use case regarding discrete USB audio and USB video devices and experienced no issues. An example of one of the USB Hubs we tested with is Amazon Basics 3.0 Powered Hub.
However, this being the case. We do not recommend exceeding the USB spec limitations of seven USB layers (Root+5 hub layers+end device).
Swytch is comprised of two layers - one layer in the active USB cable between Swytch Hub and Swytch Extender and one layer in the Swytch Hub itself.