As I've written before on HN:
A hub with multiple USB-C downstream ports cannot exist with any sort of reasonable UX. The C port supports multiple "alternate modes," which remap USB-data pins to other functions (like DisplayPort, HDMI, Thunderbolt, analog audio, etc.)
The various alternate modes are not simply transporting display/audio/Thunderbolt data over a USB channel. It's the difference between packet switching and circuit switching.
Plugging in, for example, an HDMI adapter to one downstream port affects what devices can be plugged in to other downstream ports.
A true HDMI adapter would revert all other downstream ports to USB 2.0. But... an HDMI adapter that's really a DisplayPort with internal DP -> HDMI converter can potentially allow USB 3.0 on the other downstream ports (or, potentially, ONE other port with DP and the rest with USB 2.0).
Either way, plugging in the HDMI adapter means your USB-C headphones might stop working (depending on whether they are analog or have an internal DAC).
How are users expected to understand that they need a certain type of USB-C headphones and a certain type of HDMI adapter in order for both to work at the same time?