It does sound overwhelming; it's no wonder you want to get away from the fear and suffering
What would it be like if next time the police knocked on the door, you told them: "S19 is an adult and doesn't live here. I don't have any involvement in the situation." Or, "I'm not in contact with S19 and this is no longer his residence. You can try Apartment XYZ on 123 Street -- beyond that I don't know, except that he will not live here again."
What would it be like to block his number from your phone; or, at least, to decline to respond to his texts and calls? (If you decide to do that, know that the frequency may increase briefly before dropping off. This is a normal response to change that is sometimes known as an
extinction burst).
It is normal for parents of adult children not to have their adult children live with them or move back in.
It is normal for parents of challenging adult children to have
boundaries about what amount of contact works for them (the parent).
Having normal boundaries about contact and living situation is... normal. Whether other people like it or not doesn't mean it isn't OK. It is normal to have a living situation that works for you, even if nobody else likes it.
It is OK for your love for your son to look like declining to receive his calls and texts, and declining to let him live with you or come in the house -- that may be what he needs to grow up on his own timeline.
...
I wonder what you could do today, that sounds do-able to you, that might be a change in taking back your life, and loving your son from a distance? What sounds possible -- changing something about responding texts, calls, etc? Something else? Doesn't have to be big. It could even be calling a crisis hotline (I've done this before, too -- you wouldn't be alone) and seeing what they say. In the USA, I believe 988 takes calls and texts, and 741-741 is for texts.
Let us know if you decide to try something out -- we'll be here for you.