It's difficult to compare these places, when I lived in Toronto the homeless situation was nothing like what I saw in downtown SF, even around Bloor & Yonge at night.
You'll find the situation is much more grim in the US in major cities and exactly like the OP describes. It affected me slowly over the years, I'm still recovering.
And it was definitely unsettling, I had a man follow me from the bridge back towards my neighbourhood at night.
But, I also note that Pittsburgh has relatively few such walkable neighbourhoods (though it is much better than the Us average!). If it was more like NYC or Montreal the homeless population would be more diffuse.
I’ve been to NYC a bunch and it always feels much safer. Not only were there fewer homeless per street corner, but there are always large amounts of normal people walking around, so you feel safe with numbers.
(To be clear, other than the one person following me, I felt safe in Pittsburgh. The ones in the neighbourhood I was in were not aggressive. But it was different than Canada or NYC in that they were much of the foot traffic)
[1]https://www.washingtonpost.com/dc-md-va/2019/12/03/new-york-...
Also nyc doesn’t have low per capita homeless numbers. It does however shelter them better than, say, SF.
No need to cross international borders. Vancouver BC is on par with downtown SF for this.