Perhaps this is idealistic on my end, but I had a conversation and thought restructuring police education might be beneficial. A lot of trade based occupations have multi-year training programs and internships to get a person used to the job and the skillsets required as well as scholarship style things for those who desire to pursue such careers awarded with expectation of them staying within the trade for an allotted period. In addition to the training they already receive (which is relatively short in my opinion), perhaps it would be beneficial to make the police introduction and internship program between 2-4 years, where part of the time is spent shadowing other officers so that there is a background in experience and preparation for more volatile situations, another part is spent with whatever training they do now (which I assume relates to tool training, rule and standards memorization, and self defense), and another part is taking study based classes on criminal behavior, ethics, and psychology to learn about why people behave as they do and also provide techniques about how to deal with panic situations and their own emotions. Required seminars, if they aren't required already, as well as update classes similarly to those that teachers get intermediately through service might also be beneficial.
A lot of the police violence that isn't based around racism is very connected to impulse and fear and I find that people do a bit better when they can predict a situation and know how to respond to those who might not be in good health.
It may also be good to provide better counseling services for police, especially for those in areas more inclined to violence. The rate of spouse abuse from police is relatively high and police violence in general is not much better, so perhaps providing outlets to deal with that would help reduce instances of unnecessary aggression.
I guess people might not be happy because this is the reverse of defunding the police, but overtime I think the police at least in America have become something that they weren't expected to become when the system was initially established. As their role has changed, the structure needs to as well.