I too lost quite a few files with iCloud Drive a while ago. I think there might have even been a second file sinkhole, as some of my files disappeared entirely

I too lost quite a few files with iCloud Drive a while ago. I think there might have even been a second file sinkhole, as some of my files disappeared entirely off iCloud Drive circa 2015, without showing up in the deleted/recoverable file list they had if you logged into iCloud over the web. That's not what the author describes.