Qualified Immunity didn't exist as a concept until the 1960s, and it was put in place to shield policemen enacting racist policies and corrupt cronies of Nixon.
Regardless, the police get sued all the time anyways. It's just that the burden currently falls on the taxpayers.
I fail to see how this would change anything other than increasing taxpayer costs further in the form of insurance profit margin.
Now you'll do the same thing with police, as if police wages and salaries won't increase proportionally, but 20 years from now you'll wonder why that costs so much. It's bizarre how economically imperceptive everyone is.
We are already paying increased taxes to deal with all the lawsuits we already incur because these people know they are above the law and they think it isn't their problem.
Every interaction with the police is a dice roll to see if someone lives or dies.
How many other jobs can we apply this to?
More "you say X we say Y here's your options you are Z days over with a W% rate", rather than "Ah hah! $50 dollars error, time to make an example outta this poor bastard."
Or maybe police training should be longer than a coding bootcamp... in some countries, police work is an undergraduate major and the programs are quite competitive. Similarly, there are countries without qualified immunity as a policy, and it doesn't seem to fundamentally undermine policework there.
Qualified immunity, as a concept, makes perfect sense. Police officers are not jurists, and they will make mistakes in enforcing the law. Making those officers personally liable for honest mistakes is, IMO, excessive.