I know this port that isn’t working under CoreELEC is the USB-OTG (USBv2) port for the Beelink GT1 Mini. Having done some researching, It seems CoreELEC is specifying OTG mode so It works ONLY as gadget instead of a working USB port for devices like Mouse, Keyboard and storage devices.
… In hopes there’s means for the enduser to tweak and change it’s mode. No need for OTG mode under CoreELEC.