Problem
When plugging in an audio interface via USB-to-lightning dongle into an iOS device and opening up a Zoom meeting, the audio feed does not connect with the call, despite the iOS device (in this case, an iPad 5th gen) receiving and sending the audio signal through the Zoom driver.
Solution
There is an Apple developed app calls “Audiobus” that directly can connect audio from inputs, apps, etc to each other, but Zoom does not support integration with this app. If Zoom were to support integration with this app as an input and an output, I believe the problem would be solved.
Alternatives
Other solutions would require either an iOS version of Zoom to add an audio routing feature or added support for a long list of audio interface hardware/drivers currently out there on the market.