@Joness29msu EA has announced a 64-bit-compatible version of Sims 3 for macOS, to be released (hopefully) sometime this year.
https://answers.ea.com/t5/Technical-Issues-Mac/An-announcement-for-The-Sims-3-players-on-Mac/m-p/827...
Other than that, no, there's no way to make the game run in Catalina. If you'd like to update your Mac, you could first install Mojave on an external hard drive or USB stick, then boot into that when you wanted to play. The drive would also need enough storage to hold the game and your user files. The other alternative, if your internal drive has enough free storage, is to partition it and install Windows on one side; this is known as Bootcamping. Let me know if you're interested in either option.
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I don't work for EA. I'm just trying to help fellow players with their games.
