Re-read my post above once again, as everything is very clearly stated.
The Genuine Apple Lightning to USB 3.0 adapter has the lightning port so you can connect external power using ypur Apple lightning/charge cable and Apple power/charge block plugged into a wall power main or power strip.
That adapter works with iOS 13 only compatible iPads that have a lightning connector for external drive use.
As I stated VERY clearly above, with iPads with a lightning connector, for most external drives to be detected and function that adapter must have an external source of power connected to the adapter for all of this to work!
That is the function of the lightning port on this adapter! TO SUPPLY NEEDED EXTERNAL POWER to the adapter and through to the iPad!
Some portable, high power, power banks should be able to be used to supply enough power to the iPad through the lightning port, but I have no way to test all the ones out on the market.
Some portable power banks have been reported to work, some have not.