Chiming in late to correct you a little here: QI actually means that you can’t sue a cop unless you can show they violated a clearly established law.

In practice, that means you have to find an identical (and I really do mean identical) case where the court decided the cops violated someone’s constitutional rights so you can show the court in your case, “see, the cops should have known stealing my rare coin collection while serving an unrelated search warrant was unconstitutional*.”

*a real case that really happened. The cops were granted QI bc apparently it wasn’t clearly established that literal theft is unconstitutional.