Re: My Library saves do not show up on my new device

@Luliepooh  I don't believe Steam supports cloud saving for Sims 4; EA certainly does not.  So you'll need to manually transfer your content.  Saves and other user content are in the Sims 4 folder in Documents > Electronic Arts, and you can transfer this entire folder or just the saves subfolder if you want.  Your saved households and builds are in Tray.

If you upload the content to a filehosting service, I'd suggest zipping the folder first, then unzipping it once it's on your new computer.  This can help prevent corruption during the transfer.