If the problem with your external WD drive is due to inadequate power, then a powered USB hub may help. It’s worth reiterating that whilst your drive may be formatted correctly, for compatibility with iPad, it must not have multiple partitions.
Most readily available USB hubs will present physical USB Type-A connectors; USB-C connectors are less common on anything other than the newest computers and mobile devices. You would be well advised to ensure that both the hub and any connecting cable supports USB3.0/3.1 standards as USB2.0 is quite slow by comparison.
Yes, you can connect your iPad + Lightning to USB3 Camera Adapter to the USB hub - and if the hub is powered, then you can forgo use of the auxiliary Lightning connector on the adapter for power.
As with anything iPad-related, increasing complexity of the connection tree also increases the possibility of compatibility issues.
As for the markings on your white iPad Charger, they are typically printed in very small typeface - and in a very low-contrast shade of light grey. On the white casing, you’ll need good light and good eyesight (or magnification) to read it.