I moved all of my folders into one folder, and then did an ‘organize folders’ action to resort everything into year/month folders. This means every path of my ~91k items was changed, but not the contents of them.
Desktop Mylio seemed to do fine with this change, but now my mobile mylio app can’t seem to sync it that well without crashing. It will sync for a while and then crash. My amazon drive vault I’m guessing synced this change alright too.
Edit: After restarting the app after several crashes the ios app has seemed to finish syncing. By doing this although it seems like the original sorting got half synced, so 1/9 of my stuff is still in other old folders, which the original desktop app now has synced to as the ‘new state’. This means I have to resort everything again and hopefully that syncs to my macbook, ipad and iphone properly this time.