This is the bottom line. 90% of police that I have personally interacted with (even when I've been in the wrong) have been absolute professionals and, I believe, genuinely good people. The other 10% are why I'm polite but cautious.
It would make their job more difficult, it doesn't automatically follow that they would be less effective. They might be as effective with less data if most of the data was noise, or be more effective by concentrating their efforts on fewer interactions and getting much better results from that, or become as effective or better by having to work harder. Or it might push them to develop different and better techniques.
The job of the police is to help me. To do that effectively they have to sometimes talk to me. It is therefore in my interest to talk to them.
https://www.nytimes.com/2005/06/28/politics/justices-rule-po...
Policing means arbitrating in a dispute even when no laws have been broken, helping those in our community incapable of helping themselves (accident victims, people whose meds are off). It doesn't really mean the regular use of violent force or even the threat of an immediate death penalty to gain compliance with a personally conveyed order. Tht's not justice and it's arguably not even law enforcement.
The police have immense power, you do not.
What do you have to gain from interacting with the police? Now, compare this to what you stand to lose by interacting with the police.
The rule is simple: don't interact with the police. They are not your friends, anything you do or say can and will be used against you at a whim.
Do not romanticize other countries, please.