In a nutshell: https://terikanefield.com/criminallawfaqs/

I would advise reading that page in order, and in full. It lays a lot of foundation as it goes. There is indeed a call-to-action at the end.

Our system resembles an obstacle course. One consequence of the hard work of people like Thurgood Marshall is taking power away from law enforcement and subjecting law enforcement (including prosecutors) to stringent rules. Federal Criminal Procedure is a full-semester law school course. It is mindbogglingly complex, but keep this in mind: The complexity is to create fairness.

Dear people who want the process to move more quickly: Be careful what you wish for. Giving more power to law enforcement (and prosecutors are part of law enforcement) might bring about the short-term results you want, but is not a good idea in the long run.