You're half right but missing the point.
Police probably shouldn't be sued for performing their duties. But the issue is that with a few choice words (I feared for my safety/life) their "duties" cover a wide array of actions that a lot of citizens would argue it shouldn't.
Example: There are many cases of Cops stepping in front of a moving vehicle when confronting a suspect, which then is used as a reason to shoot and kill the suspect because "their life was in danger". But it's very easy to argue that the Cop put their own life in danger by stepping in front of the vehicle. IMO, that should not be covered by qualified immunity, and yet it usually is.
My point is that qualified immunity is not the problem. In your example, the cop should be prosecuted. Qualified immunity doesn't cover criminal prosecution, and a lack of prosecution has nothing to do with qualified immunity. Being able to sue that cop would be a nice bonus, but what you really need is for the cop to be criminally prosecuted for their crime.
Getting rid of qualified immunity wouldn't do jack squat to change that. The problem is an informal culture where police are not prosecuted (or if prosecuted, not convicted) for crimes.