Deleted saves and Sims coming back

@Wilvin22  This is an issue with cloud storage, but not saving through Origin.  Instead, the likely culprit is OneDrive automatically syncing the contents of Documents, uploading your saves and then redownloading any "missing" files when it detects them.  The simplest approach is to prevent OneDrive from auto-syncing Documents:

https://support.microsoft.com/en-us/office/choose-which-onedrive-folders-to-sync-to-your-computer-98b8b011-8b94-419b-aa95-a14ff2415e85

When you do this, your Sims 4 user folder may be removed from your computer, leaving only the copy in OneDrive.  But you can simply redownload the folder and put it back in the local version of Documents > Electronic Arts.