“This is a USB C plugged power unit (It's not a USBC device) but it's not really fit for the job. It's barely got enough power for the Pi4 and a single external drive. If you want to fit two drives, i.e. to make up a NAS then forget it. (I doubt if most users would notice the problems)
So now I've got to build a decent power unit -
Noty a problem I expected this.
I know why USB power was chosen, but I can't help saying it was the wrong choice . A couple of screw terminals or a robust 2 pin power connector is what was needed.”