I can't find my last edited save

How are we supposed to help? You haven't told us a thing! For a start, is this on a Mac or a PC? When you say 'backups' you do realise that the only thing being backed up is your session file, don't you? No audio is backed up. Where is the backup location set to?

The 'normal' way to make a session secure is to store it locally on your machine in a folder of its own, with copies of any audio associated with it in there as well. Anything at all less than this is inherently risky. The riskiest thing of all is to save your backup session files to any form of cloud-based storage, because if you lose access to that (it's the internet, after all) then fundamentally, you're stuffed. I'm sorry, but I can't think of a politer way of putting it. So if it's a session, then that's what you need to investigate - where the backup folder actually is.