Bulk moved files from Dropbox to iCloud, moved files now showing as zero KB

Hello community. Yesterday, I began to attempt to move many, many files that I've been keeping on Dropbox onto iCloud for consolidation purposes. We're talking thousands of dry but important documents like old tax returns, birth and death certificates, old project files etc. To do this I had simply opened two folder windows (one Dropbox and one iCloud) and manually moved things from one to the other, attempting to organise into new folder structures as I did so. Today, 10 hours later, a large number of the moved files are showing as zero KB in iCloud and I can't open them. iCloud appears to still be syncing, and Dropbox also, although its been stuck at 48,003 files syncing for the last hour. Should I wait to see if things will sync and right themselves, and if so how long might that be? (I'm not sure how to tell how many GB I've attempted to move). Or should I pull the plug now and attempt a restart and try to use the rewind feature on Dropbox? I'm starting to panic a little as these are things I really don't want to lose, so any suggestions would be great!