Re: Is bit-rot a real phenomena? - SHOULD
@Duncan MacDonald
Perhaps I've misunderstood your point, or perhaps you jest. This functionality has been part of macOS and iOS for donkeys now. On macOS it's called time machine, on iOS it's just called backup. On macOS you have the option of backing up to a locally connected disk drive, or to a location on the network. On iOS you can backup to a connected Mac or to iCloud.
In either case, you can choose to locate your documents folder and desktop (and more besides) on iCloud - so that everything is kept backed up and synchronised at all times.
Do you want more than this? It's pretty seamless, straightforward and easy to set up…