Police carrying insurance, like other professionals such as doctors and licensed engineers carry, would fix this problem for the city, and also improve civil rights for the citizens. Bad cops would have their insurance pay for the liability they are found for. Their insurance premiums would increase to account for their bad behavior. Bad cops would eventually not be able to afford the sky high rates from their bad behavior and not be employable as cops anymore.
I’m even fine if a city would pay for the base insurance, but any premium increases from judgments of bad behavior would be born by the officer that caused it. This way good cops aren’t burdened by the actions of the bad ones.
I will forever stand on mandatng cops get malpractice insurance, making the city pay the “good cop” premium, and making the individual cop pay anything beyond that.