The problem you run into is needing to front load the resources. You cant remove those funds from the police, and then start spending it on social workers/crises intervention specialists, medical, education, because the gap will be too great. That reduced funding to the police will translate to less police, then because the solution isn't in place, the police will still be relied on as the catch all, but with less of them, they will be more likely to use force, which will lead to more lethal force use.

First you need to provide extensive national standardised training for crises intervention and de-escalation to police so they have the resources to better intervene with persons in crises (they will do a lot of this intervention even in the new world order of defunding, because no social worker is going to talk down a guy in crises with a bat without a guy with a gun making it safe first, so it won't be wasted).

Then you need to fund these new resources and allow them to take effect before removing resources from police.

Unfortunately immediately cutting millions of dollars and giving it to social programs and medical field, won't have the desired effect because those fields face significant shortages of employees with their current staffing levels. If you suddenly make thousands of more positions available, you won't have anymore people to go into the job.