@Nyeisha14 Please make sure your saves and Tray files are in the folder Sims 4 is reading. Here's how to find that folder:
https://sims4.crinrict.com/eng/2018/07/how-to-find-your-user-folder/
Make sure the file paths match exactly, at least up to "The Sims 4." For example, if one of the folders is in OneDrive and the other is not, it would explain the issue.
If that's not the problem, please post screenshots of the contents of the saves and Tray folders, as in, I'd like to see the file names and dates myself. Include the address bar, above the list of files, in the screenshots.
Here are the screenshots The tray had way more files in it and they disappeared.
