This may not apply everywhere in the US, but my understanding is that most cops aren't paid terribly well. Perhaps it's ok if compared to a standard job, but when you account for the danger, required over time, and work schedule it becomes very not worth it.
A buddy of mine is a true believer type, he signed up to be a cop, went through a year of training and another year paired with another cop. PreCovid starting pay was $40k, 12 hr work schedule and every 28 days it flipped (so 28 days day shift followed by 28 days of night shift). One day he gets a call and his boss had switched him to a different district with 3x the commute without any communication. Finally a buddy of his caught a bullet in the head (and lived) from some guy who was on drugs and stole a car. He said he thought about it and for the money it wasn't worth the emotional cost.
Strangely the problem with underfunding cops is who the fuck wants to be a cop? Yeah, after 25 years and multiple promotions you might make an ok or even good salary, but being a new cop is absolutely shit. In a system where the pay isn't good, the hours are shit, and the risk to your life is high, who wants to be a cop?
The answer is either self sacrificing good guys or people who get a power trip on carrying a gun and using it. Add to it that this system is perpetuated by the type of people who pursue the job you end up with a whole department full of the type who hire these types.
So while you can defund the police, you can send them through training, you can institute new policy, but if you don't attract a better quality of person then you're gonna have the same problem over and over again.
Theoretically you could make the hours better (but that will require hiring more police to cover the same amount), you could reduce the danger (similar to London banning guns so beat cops don't carry them either), or you can pay them more.