Arrests are not necessary in the vast majority of situations police are called for, and recording technology is far superior to verbal testimony for serving our courts
It will cost more but what if we pair cops with non cop observers or participants? Like someone trained to talk with people and asses rather than just bust heads. Maybe it could even be volunteer sign a waiver and be a community observer? Or jury duty style even.
Then, if head busting is actually needed (and sadly occasionally it is, please don't be naive) the head buster is on hand. But it should be much rarer.
Something like balance of power in government to prevent one party from doing whatever it wants. That is what seems to be what is missing in police work. It's all one sided and few checks and balances.
Considering how much is spent on weapons training, this would likely be a net cost reduction. "Camera cops" could probably be paid less because they would have less risk of being in violent situations, don't have mental anguish of making life or death decisions daily, and less animosity from the community.