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Check iCloud although we should have seen a path to it in the Terminal search https://answers.ea.com/t5/Technical-Issues-Mac/READ-FIRST-Saves-CC-Mods-or-Library-items-disappeared/m-p/10242133#M45493
I'm going to move your thread over to the Gameplay board for further help and input regarding Scenarios now we've exhausted any possible Mac specific issues. Unfortunately it does seem like you've wiped your saves and there's no getting them back although maybe you could restore an old save from your Time Machine backup?
Your Time Machine backup from last summer is probably the best you can do. ☹️
If you have some kind of external hard drive or something like that, you can copy your saves over every time you play. (I used to do that manually but now have a script, but it's for Windows.) You might want to consider that in the future if you're not going to back up your Mac regularly. ☹️
