Using Nikon Z6 and XQD cards current workflow is to plug Sony XQD card reader into iMac and using Lightroom CC on macOS Mojave import directly into Lightroom using the "+" menu and the XQD card shows as a choice.
I shoot in raw and do not want to use Apple camera roll /photos app at all. This works fine on desktop or macOS laptop, but I was hoping with the release of iOS 13 and greater support for external storage drives/cards in the "files" app to develop a reliable workflow when traveling using only iPad Pro and XQD card reader.
iPad Pro 12.9" 3rd generation (the one with magnetic pencil holder on top edge)
Apple USB-C to USB-A dongle cable
Sony XQD card reader with USB-A cable
Lightroom CC mobile for iOS
Sadly, there is no menu choice or option in Lightroom CC mobile to see the attached XQD storage card. The only options are still to import from the camera roll or from a file folder. (Hoping this is will be added in an update by Adobe sooner rather than later!!)
Since I don't want to pollute my iOS/Apple camera roll, I use the updated iOS "Files" app to copy all the raw files from the XQD card to the iPad.
To keep it simple and avoid introducing more complexity, I drill down through the XQD folders and select the lowest level folder that contains all the photos.
I select that folder, then select "Copy" from the "Files" menu strip on the bottom of the screen. I then navigate in the left-side list of destinations to the "On my iPad" folder and paste the folder there.
After a long delay, the files are copied. I drill down into the copied folder and delete the one non-image file that came in from the XQD card.
Note that the raw photo files are now entirely on the iPad in a local folder. Just to be clear, this eliminates the dongle and XQD card reader from the workflow so I know there isn't a problem with USB cables, XQD card power, or other factors that could be wonky or intermittent.
I also did not put the photos in an iCloud folder or the new "downloads" folder - both of which would trigger immediate uploads back to Apple cloud locations (not Adobe) that would suck up bandwidth and/or cpu processing power of the iPad.
I launch Lightroom Mobile CC, select add photos, select the folder locally on my iPad and then wait. And wait. And wait. And wait. Nothing seems to happen. The "Files" app doesn't show any activity, is not locked up, the iPad is not locked-up, just never seems to do anything.
If I move back out the Springboard desktop, and go back into Lightroom, no photos have been added.
If I leave Lightroom CC open on my desktop iMac, it doesn't show any new photos, confirming nothing was imported.
My XQD card has about 60 raw files. Yes, I'm not trying to import a small number of photos - like 1 or 2, but I'm not trying to import a very large photo shoot like 500 or 1000 files either!
So, is this just totally buggy behavior or am I doing something wrong?
I don't want to use USB-C cable directly to the camera as an alternative as that:
Ties up the camera for long periods of time
Uses up the camera battery
Is known to be very slow importing speed (but I guess it does at least work?)
I'll start by echoing your comment that Adobe adds deeper support for external cards in an update soon!
I've been testing (and we're about to deploy) a very simialr workflow and the import is working fine here. But I did notice a difference in my workflow vs yours that might be the difference...
In your final step, you said the following: "I launch Lightroom Mobile CC, select add photos, select the folder locally on my iPad and then wait. And wait. And wait. And wait. Nothing seems to happen. The "Files" app doesn't show any activity, is not locked up, the iPad is not locked-up, just never seems to do anything."
What I do on that last step is to go into the actual folder with all the photos, click on "Select" (upper right), then "Select All" (upper left), then "Open" (upper right). The photos appear in LR!
I think the issue you're having is trying to use "Select" on the folder. Try going inside the folder, selecting all and then clicking on "Open".
Strange... I'm not having a problem with large amounts of photos (I did one set of about 300). The only other potential difference is that I am running the public beta of iOS 13.2. But the problem you're having feels like it would be more a LR issue vs an operating system issue. You're sure LR is up to date on your iPad, right? Mine says v. 4.4.4 62A64D in Settings/About.