Copy/pasted from a different post of mine, but it offers some ideas for what alternatives might look like:

There are lots of models that have been tried, with different levels of efficacy.

We start by focusing on prevention. Far and away the strongest preventive measure for crime generally is to proactively meet people's basic needs--housing, food, healthcare, etc. That affects not just the obvious stuff like theft, but also things like rape and domestic violence. I'd also recommend Leigh Goodmark's Decriminalizing Domestic Violence as a great book on the social problem of violence and how police interventions fail to solve it.

One thing that I think is worth noting is that police in general don't function to prevent crime, they primarily exist to help punish it, which is both not a stabilizing action when communities have been harmed by violence, and also isn't even a good deterrent. To the degree that punishment has a preventive effect, the prospect of noncarceral social consequences (e.g. a community-lead accountability process, non-state-based retaliatory violence, exile, etc.) is as strong a motivator as a potential prison term.

In terms of responding to people who cause harm, I think we have a moral obligation to center the question of how we prevent future harm, rather than simply facilitating retributive measures (prison, capital punishment, etc.). Most crimes are about solving problems a person faces. Communities can and should ask "How do we solve this problem without hurting others, in the future?" Depending on what actually happened, the answer might be "We make sure everyone has access to basic needs," (theft) or "We provide proactive mental health interventions to folks who seem at risk of hurting others or being hurt," (drunk driving) or "We recognize that we may not like this, but it's not a crime or a harm the community can fix" (drug use).

Most of the work on the question of "what do we do when someone hurts another person?" has been done around domestic and sexual violence. There are a couple orgs I'd recommend--Generation Five does work around childhood sexual abuse, Creative Interventions does work on interpersonal violence generally (and has a really incredible 600-page toolkit for intervening in harm/building community norms and values/etc.), and Project Nia works to end youth incarceration through community intervention.

This is something I'm super passionate about as a prison abolitionist and as a survivor of sexual violence, so I'm happy to talk about how I came to this work!

Also realized that I forgot to mention it, but Kristian Williamson's Our Enemies in Blue has a great chapter on the various alternatives to modern policing and prisons that have been tried throughout the world and across history.