@sczelaya From your screenshots, OneDrive is syncing your files, and I'm wondering if that's at least part of the issue here. Do you want to keep using OneDrive? There are ways to make this work and ways to get rid of it, all covered here if you're interested:
https://answers.ea.com/t5/Technical-Issues-PC/CURRENT-ISSUE-Sims-4-saves-user-content-disappearing-PC/m-p/12475370#M249772
The current question is whether your saves and Tray items (what you've saved to the in-game library) are in the folder Sims 4 is reading. I can't tell from the screenshot because I don't know the file path to that folder. So please find that file path, as described in the link I posted before:
https://sims4.crinrict.com/eng/2018/07/how-to-find-your-user-folder/
And compare it to the full file path to one of your saves or something else that isn't loading. You can see most of the file path in the address bar in your screenshots, but to get the exact location, please right-click one of the files and select Properties > General. The Location is the file path, and it has to match the one you see in-game exactly. For example, if one of the file paths lists OneDrive but the other does not, that would explain the issue.
If you can't figure out what's going on yourself, please post the in-game file path as well as one from one of your saves that isn't loading. As a side note, the saves in your screenshot are all from December and earlier. I don't know whether this is expected or you have newer saves whose files have disappeared; if you need help finding them, the guide I've posted (first link) has instructions for that too.