Here is your solution! I actually wrote it up yesterday after responding too many times to this problem, so I could just send this link.
Hopefully, all the files are still on the iPad. If so, then just delete what got transferred and start over. If files with 0 bytes are there on My Cloud, the app will think the files are already there (and OK)…
Another tip, put iPad closer to router so transfer takes less time, and use 5G wireless if you have it set up. You can just tell app toe select ALL of camera roll and off they go. You can also set up auto-backup, so explore in app settings these options beforehand.
Her is your solution: (lucky you)