@JordanRN How long are you waiting to see whether Sunlit Tides downloads? I've noticed that worlds show up as an object for a while before the download finishes, and then the thumbnail changes.
If this isn't the issue for you, please go into Documents > Electronic Arts > The Sims 3 and move the Downloads folder to the desktop. This will remove all the Sims3Packs you've downloaded, but it won't affect anything already installed. You can just delete the Downloads folder if it doesn't have anything you want to save, but if you've downloaded custom content in Sims3Pack form, you may want to preserve the folder so you don't have to hunt down that cc again.
Anyway, open the launcher, try to download Sunlit Tides again, wait at least five minutes (more if you have slow internet), and see whether it ever shows up as a world. If not, move the entire Sims 3 folder to the desktop and try again.