Lots being deleted from gallery.

@RetroLeoxoCould you tell us a bit more about the hardware you're using as it might help to get the attention of the right player on PC/Console who might have some insight for you as to why it's happening. If EA say there's nothing you can do then I'm not sure if anyone here can give you better advice but the more info you give about your platform the better. Also, are you getting any error codes?

I'm on Xbox Series S but on my previous Xbox One this happened to me twice. I lost my entire game after 2 big summer updates 2019/2020. I spent a year rebuilding it and then it happened again with the next summer update but the second time it didn't wipe my library and I could restore my lots and families, but I had lost all of my familial links, I could re-establish some in CAS but all of my extended families were spread across worlds and not related any more. I was pretty gutted as all of their backstories were created with a lot of thought and it was all gone. I then started getting an error code and losing saves every time I used the gallery so I had to stop using it altogether.
I ended up replacing my hardware and upgrading. I'd spent hours on the phone to Microsoft who were really kind but couldn't really help me. They got me to uninstall and reinstall everything but my game was so unstable that I just decided a new console was the answer. I still have big issues with my game though, just different ones.

@RetroLeoxo  When you say your lots get deleted from the Gallery, do you mean the online Gallery or from "My Library"?  Your library is stored locally on your computer or console, not online.  If this is the issue, please let me know what system you play on: PC, Mac, or console.  If you have a Mac or a Windows PC, let me know whether iCloud or OneDrive, respectively, is active, and if so, whether it's full or close to it.

Yes, all the lots I've saved to my gallery AND library are being erased, I uploaded some of the lots to the profile gallery to see if that would prevent them from being erased but it didn't stop it at all, they also got erased.

I have a Windows PC with a connected/synced one drive that is working perfectly fine for everything else despite EA telling me there's something wrong with my "offline sync" when I haven't played in offline mode in over three years, so I have no idea how that helps me since I never make anything or even play in offline mode so I have no clue how that impacts the me, the storage is also very much free, it's nowhere near full or even close to halfway full.

I get zero error codes, nothing pops up to indicate any issues, I just close the app, reopen it and suddenly all my lots I saved are gone and households from 2019 that I deleted in 2019 are being restored as well as other more recently deleted households and game saves I deleted get restored. Even all the Maxis base game builds are gone, like completely wiped and all this happened after the most recent update. 

I have no clue what's happened to my game as I haven't touched any of the files and I haven't used mods in over four years so I know it isn't any mod corruptions.

The issue is that everytime I email EA support, I give them a very indepth list of my problems and break them down and they always, without fail, start talking about problems that have absolutely nothing to do with the issue I'm facing, like not even a little bit, it's almost as if they never actually read my email instead first place or tell me they can't help me with something that falls under the categories they said they can help me with. It drives me crazy.

I get zero error codes and nothing ever pops up to indicate that there are any issues/problems, I have literally no clue why this is happening suddenly after their most recent update and their support team can't even seem to actually read my emails and it's incredibly frustrating because I know it's nothing to do with my pc because nothing else is impacted, literally nothing else, just Sims which indicates this is an EA/Sims issue.

Usually if it's to do with my pc, my League of Legends would be impacted or the other games I have installed, but none of them are in any way, not even a tiny bit.

@RetroLeoxo  For your in-game library, it sounds very much like OneDrive is syncing your files by deleting the new ones and redownloading the old.  You could try removing the old Sims 4 content from OneDrive, or at least the Tray folder; if there's something you want to keep, back it up elsewhere.

Please also check OneDrive for any newer files, especially in Tray, that are dated recently but have additional text in their names.  For example, there might be a ⚽ at the end, or some other number; or you might see your computer name, e.g. DESKTOP-[some characters].  Or the Tray folder itself might be renamed.  OneDrive does this to avoid duplicate names and to notate where the files originated.  But in either case, the game can't read those files when the names have the extra text.

If you find newer files you want to recover, just delete the extra characters in the name.  You can see examples of the correct file formats here:

https://www.carls-sims-4-guide.com/forum/index.php?topic=26535.0

For the Gallery issue, if this is only happening recently, that may be because the Gallery is having intermittent outages.  But it's also possible that the issue with your in-game library, whatever that turns out to be, is happening before the Gallery upload succeeds.  So if you fix the former, the latter may be resolved as well.