@hanhbarraclooo This is probably not at all related to the amount of custom content you're trying to install. It's much more likely that at least one download is broken or comes bundled with a broken item. There's no good way to find out other than to test.
In general, rather than installing the content into your existing Sims 3 folder and likely corrupting it, when you want to install something you've downloaded, preemptively move the existing user folder and test the download in a new folder. If the launcher crashes, you can't use that item. If it doesn't crash, test the content in-game, and if you see any weirdness, get rid of it. If everything seems fine, you can add it to your main folder.
For now, I'd suggest installing the entire pile, a few items at a time, into a clean user folder, then setting aside any items that make the launcher or game crash or otherwise behave abnormally. It's more work on the front end but a lot better than losing saves or rebuilding your other installed content from scratch. By the way, the saves in a folder you have to trash are likely still intact and can be transferred to the new Sims 3 folder. If you never loaded the saves with the custom content installed, there's no reason they'd be affected at all.
