That's actually not what qualified immunity means...
Qualified Immunity only cover civil case, because the government don't want financial burden to impede Law Enforcement Officer or Agency. Since everyone can sue civilly, and if everyone can sue, then basically that can paralyse a department if they were hit by lawsuit left and right. So they cannot be sued civilly, which is why many civil lawsuits against Police Brutality are filed against the city or state that employ that police force. Any officer would still be held legally and criminally accountable if a crime is committed by a LEO (an organisation or agency cannot be criminal responsible for a criminal charge due to absolute entity)
Qualified Immunity also does not work if the department or the officer is not act on an action of clearly established law requirement. This part is a bit tricky because this is an objective measure. But mostly you can define them with 2 examples. Qualified Immunity will applies if a cop or an agency violate your 4A right and perform an illegal search, however, that only applies if the officer knows the search would violate someone's 4A right and went ahead and do it anyway, for example, if a cop obtained a search warrant to search your house, and mistakenly belief that they also have the right to search your shed in the garden where it was not specified (House usually means inside the home) and searched the shed, while that is a violation of your 4A right, Qualified Immunity would applies.
Another example is when a police discharge their weapon negligently, but without the intent to harm (say he/she fire 4 times instead of 1 or 2) that also covered by Qualified Immunity, however, if the cop intent to do that to cause harm (say the suspect is down and he/she continue to shoot) that's a criminal act and not covered by Qualified Immunity
Qualified immunity needs to be abolished, and then cops will be liable for the crimes they perpetrate on the citizenry. Your US taxpayer will not have to pay out for The Millions and millions of dollars for the lawsuits that they cause!