There are many countries where it has been proven that less aggressive policing, with the funds instead invested in social community services has resulted in less crime and safer neighborhoods.

Same applies in the other way: the UK has seen a massive increase in gang violence because of years of austerity, during which social community services were cut. Combined with ever increasing gentrification, this has resulted in bigger and more violent gangs because the ones at the bottom of the financial chain had no places to go to anymore where they could build (safe) social circles, as well as get assistance in how to grow professionally and become full-time earners.

It's the police union that makes it difficult to hold police accountable.

This is one of the biggest issues, especially because many local Union leaders joined the squad in the 80s, early 90s and were trained in offensive and oppressive policing reactions. With a president like Trump, and his asslicking GOP governors, they are reinforced in their old-school beliefs and methods.