PowerExpand 8-in-1 USB-C hub A8380 HDMI ports not available

On my Asus motherboard ROG STRIX B550-F using the USB3.2 connector i have absolutely no signal on either HDMI port. They don’t show up in device manager.
All other ports are working and the NIC installed fine as plug and play.
I am using an AMD 5800X CPU with no integrated graphics. The graphics card is an Nvidia RTX 3070.
Any suggestions how to get the HDMI ports working?