Hi Sapro,
Please ignore the first part of my reply above (iCloud Drive still is not supported, but you were talking about iCloud Backup).
iCloud backup is handled by Apple and there is nothing we can do about it unfortunately. It might take a while to restore lots of files from a duration of a year and a half. Did you give it a try to let the device restore over night?
I’d suggest to get in touch with Apple about the issue.
Nevertheless and as mentioned above:
Make sure to backup your projects on a regular basis separately (iTunes File Sharing is a good option)!
Best,
Lars