Sylviavioletbaby Installing content through the launcher doesn't work in the most current versions of macOS. This is the master thread, and there's a workaround (install through the Dashboard at the Main Menu) described in the thread:
Launcher crashes when I open the downloads tab in Sims 3 | EA Forums - 12167613
For the custom content that won't load in-game, did you also delete the cache files in your Sims 3 user folder? These need to be deleted every time you add or remove content from the folder.
- CASPartCache.package
- compositorCache.package
- scriptCache.package
- simCompositorCache.package
- socialCache.package
If that's not the issue, please confirm that the Sims 3 folder you're working with is the one the game is currently reading. You can check the date modified on DeviceConfig—it should match the last time you opened the game. And just to be clear, these are all .package files, right? Sims3Packs need to be installed through the launcher (which you can't do), and .zip or .rar files need to be extracted.
The eyelashes looking wrong is an issue with this version of macOS and not solvable except by minimizing or removing the EA eyelashes and applying cc eyelashes instead.