[nibbleshifter]

A combination of "supported" and "independent living" housing options is optimal, using shelters as a short term onboarding and sorting facility.

This also requires a solid policy around social and affordable housing as part of mixed use developments (as opposed to creating social housing "ghettos").

Needle exchanges and safe consumption facilities can be used for initial contact and outreach.

Basically you need to get people into a position where you can help them, then help them to the point where they can help themselves, and provide realistic pathways for this to happen - along with avoiding unrealistic expectations and avoiding pointless gate keeping such as demanding service users remaining clean/sober, etc.

Think of it as solving for Maslow's hierarchy of needs. You can fix their drug and mental issues later, right now you need them off the street where they get food/heat/water/shelter, health support, etc.