LocalSend with an honorable mention to KDE Connect
I had had tens of gigabytes to move off of an iPad and was quite concerned about the file corruption issues that can occur when using iOS's native file manager to copy or move files to external storage.
I was too new to the recommendation of the 3rd party file manager for iOS and MacOS called FileBrowser.
I tried two recommendations LocalSend and KDE Connect. They are both availalable for multiple operating systems including Android and iOS. I stopped using KDE Connect early on because LocalSend has two features really useful to me that so far KDE Connect appears to lack: transfer speed and estimated time for the file transfer.
Despite the apparent lack of any mention of it in LocalSend's documentation, I can transfer files between iOS and Android either WiFi to Wifi or WiFi to Ethernet.
LocalSend appears to be a project actively worked on judging by the regular notifications of updates through Obtanium. A few months ago when LocalSend was several versions older, I had to first compress multiple folders in iOS into one prior to sending it; but maybe I was just too new to LocalSend to figure out how to send the folders individually. I've used LocalSend to send up to 12gb at once; it took several minutes before LocalSend was ready to transmit it to Android. Speaking in general, the transfer rate is usually 8-11 MB/s and am assuming the capabilities of my router are the bottleneck; the transfer speed using LocalSend is appreciably improved by connecting one of the two devices by ethernet.
Because it is such a chore to set up a lightning-based iOS device for an ethernet connection, I instead connect my Pixel phone via a Best Buy private label USB-C to Ethernet Adapter; I have been surprised to discover that some of their private label products have been of a good quality.
Here are links to what I referenced:
File corruption on copy to external storage
https://forums.macrumors.com/threads/file-corruption-on-copy-to-external-storage.2235171/
FileBrowser
https://www.stratospherix.com
KDE Connect
https://invent.kde.org/network/kdeconnect-kde
LocalSend
https://github.com/localsend/localsend
https://www.bestbuy.com/site/best-buy-essentials-usb-c-to-ethernet-adapter-white/6523711.p?skuId=6523711
N.B. My model "Best Buy Platinum" seems to be discontinued at this time; hopefully this "Best Buy Essentials" model is as capable.