Again, you're dealing with "professions". I'm dealing with "humans". All fallible - all imperfect. You may say "police should be ..." this and that, but reality says they're not. You can say training police officers may help, and it may very well help some/many. I don't know. But how about we train everybody? Or at least have the common decency not to do stupid crap? Then a lot of this can be avoided. But again that would be a utopia, and I don't live in one, nor do I ever expect to because we're all fallible human beings. I never provided any "solution" (despite your claim) because in most circumstances I think the "solution" is often, if not always, left to the individual. "I choose not to commit a crime today", "I choose not to beat down a subdued criminal today", "I choose not to stand by and allow my co-worker to beat down a subdued criminal today", etc. All individual choices that were made that day. If you think "housing" and "mental health" checks can help, by all means, espouse that -- I'm not against it.
Choices have consequences and that Is why I’ve always felt the most needed reform is to hold LEO accountable through the justice system. Prosecutors need to be willing to indict LEO that exceed their authority and other LEO need to be willing to testify against LEO.