If Joe Biden is your example of the Far Left, you are oddly confused. What the DSA (and they are idealists, but it's okay to have ideals) say that they want about the police is:
"Demilitarize police departments, disempower police unions, and redirect funding to public services as steps towards fully abolishing the police and prison system which protects the rich and jails the poor. Treat drug addiction and mental illness as health issues, not crimes. End qualified immunity and empower civilian oversight bodies with real authority over the police."
So, to demilitarize the police means having them less heavily armed, less set to kill people (they kill 800-1000 people each year). Police unions (and prison guard unions) are a major force in the push to incarcerate more and more people for longer each year (something that costs us a lot of government $, destroys families and communities, and does not reform the imprisoned people. Oh, and it puts us firmly in the 3rd world class of countries.
Redirecting funding towards public services make sense. Do you want long-term homeless people arrested, or getting mental health counseling, job training, and support towards finding homes? Do you think that drug addiction and mental illness are health issues, or do you think that imprisoning people who suffer from them will make them better?
Ending qualified immunity means making sure that there is community oversight to keep the small percentage of rogue cops from harming or killing people.
Once you think about them, don't those sound like good ideals to have?