The state, no matter the ideology of the members of the apparatus, needs their goons for when they want to crack down on their personal version of Emmanuel Goldstein.

If you want the police to de-escalate, training will do no good, because they will still turn to force when stressed. Disarming the police will only up the ante on militarization, because whenever the everyday patrol cops get into trouble, they're going to be calling out tactical forces with full armor and automatic weapons (it's very weird, BTW, to watch shows or movies set in contemporary UK and hear the cops say "Armed police!" when going after bad guys; in America, the modifier is taken for granted, because once upon a time 'armed' was not an unusual state of affairs for anyone in America). And without that backup, they aren't going to lift a finger for anything remotely dangerous. All it took was a moderately bad cold that has killed almost no one young enough or fit enough to be a police officer to make them abandon altogether traffic stops or entering homes for first aid or dispute resolution. Once they don't have guns, you can forget all that. Traffic tickets will be issued by computers linked to cameras or radar, or at roadside checkpoints with SWAT cops for security. If the cops or EMT need to get a sick or hurt person out of bed or off the floor, they're going to make everyone in the residence come out front and put on cuffs before they go in.

A better way to go about it would be to strip them of special privileged. If the cops want to carry a piece of equipment, the general public had better be able to get it on Amazon or at a gas station convenience store. The cops should stripped of their 'good faith' immunity and subjected to the same rules about assault as everyone else, with a higher standard of proof for charging assault on a police officer than "me and all my work buddies swear he swung first, honest!"

Give them real motives for de-escalation, like "don't wanna get my ass kicked." As it is, there will never be any respect for such efforts because their proponents have no real understanding of what confrontations entail. They do those exercises where they give a reform advocate or police critic a paintball gun and turn him loose in a set of simulated encounters, and the advocate usually fails and proves way more trigger happy than the average cop. So even the honest cops, who want to do a good job and avoid trouble, dismiss the input of such types out of hand.

You'll never stop the cops from defending themselves, so the best recourse is to let people defend themselves from the cops. That is what will make them more cautious and willing to use words instead of going over the top as the unquestionable authority figure in any given situation. And start letting people set up claymores in the foyer in case of no-knock warrants. There is no excuse, no justification for that. If you need tactical surprise, you're already a failure as peacekeepers.