@Dennis Meints tough situation, I'm in something similar with a duplex in the North End Neighborhood of St Paul right now. My thoughts are just keep grinding ahead. I think the fundamentals of the city are strong, and I agree that there are decent people around and there is pride in the neighborhood. Really, it isn't such as bad area, I think ppl who've been to a truly bad area would find it very decent..
About property manager, 145 is frankly high, 100/unit/month is what you should pay.
I think you've had some bad luck and further difficulty with the rent moratorium, but I think your strategy is not all bad. You might consider renting on free market (not sec 8). Seems like when you get into a building bigger than a duplex, the lack of pride of rentership in sec 8 really makes management tough, unless its a truly specialized company. You might consider marketing to a group home, or making it a 55+ community, etc (guaranteed rent, more supervision, less feisty renters).
Before renting it again, try to touch base with your manager about really repositioning the place, give the impression its a clean/ safe/ decent place to live, decent bright exterior and interior, etc.
Like I said before, really nowhere in Minneapolis/ St Paul is too bad.. compared with the rust belt cities, etc. Anywhere where a burnt shells are selling for 90-100k is going to be somewhat decent.
Just keep at it and you'll get through this!