The PeerTube instance that I have been uploading to is no more. I think there are around 70 edits of mine that are no longer accessible. If there was a catbox link, they may still work. This represents hundreds of hours of work that I did that have simply vanished. If a link is broken, let me know and I can see if I still have the files for it. Thank you all for watching the things I’ve made/
You’re suppose to be able to log into a new device and recover all of your files. But I have heard horror stories (particularly involving Dropbox) where the lack of files on the new device confused the service into syncing that blank slate across all devices. I have personally had issues with iCloud where I delete a file and try to re-add it only for iCloud to keep re-deleting the file every time because it thinks it forgot to remove them all.
Cloud syncing is not built with backing up in mind. In situations where the syncing service becomes your only copy of everything and you do recover it all, you’re just lucky nothing happened before you got to it.