Retropie + Raspberry Pi 4 - no USB

[cmcpress]

Specs:

Raspberry Pi4 + 4GB Ram.
Retropie installed from Raspberry Pi Imager - updated

I've installed the drivers as per the instructions from here:

https://github.com/DeskPi-Team/deskpi_v1

and updated the config file with dtoverlay=dwc2,dr_mode=host

However the USB ports do not seem to work. If I plug a portable drive in, I get power but the system does not recognise it. Similarly a USB mouse is not recognised.

Are you able to help?