@TinyMole3 It looks like you've installed Sims 4 through both Steam and the EA App. I'm guessing you're playing through the EA App now because the Steam version is missing a folder that the most recent patch would have added. Realm of Magic is definitely installed into the Steam version and not the EA version; the same may be true for Cats & Dogs.
The first step here is to pick one version, Steam or EA, and uninstall the other one. If you own RoM or C&D through Steam, you'll need to play through Steam in order to access the packs. If you own them through the EA App, you can choose either one.
If you want to play through Steam, just uninstall the EA App version and launch the game through Steam; you don't need to do anything else. If you want to play through the EA App, once you've uninstalled the Steam version, clear the App's cache:
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
then download your missing packs again.