Four means to improve:
1. Bail proportionate to their crime and past criminal record;
2. Stop plea-bargaining away felonies for violent crimes;
3. Stop early releases of criminals for Covid or other pretexts (Covid is the current "reason", but other "reasons" will come along at "need");
4. Tighten up use of the death penalty - evidence required for conviction and the capital sentence, limit time for appeals and require all bases for appeal to be litigated together, schedule executions to happen within 1 year of the last appeal.
Get the thugs off the streets and murders will decrease.
A 5th means of improvement would be for police and prosecutors to "sweat the small stuff". When the risk and cost in the "small stuff" is significant, less "small" and "big" stuff will happen.