One idea is Equity Participation where an investor pays for the down payment and the homeowner occupant pays mo.ly bills, some or all: repairs, maintenance, capital improvements. That is assuming income is available to pay loan balance, interest, insurance, taxes. Then both agree to sell in 5? yrs and split the profit (assuming there is one) whether 50/50; 40/60. Tv infomercial described a man who co-owned 200 houses around the US, each contract  different. A good job for an aspiring lawyer or team?

One problem years ago when I looked into Equity Participation was some confusion as to which party gets the tax benefits. Most CPAs could answer that and perhaps even suggest working coownership or other ownership proposals.

Limited partnerships have existed for decades: perhaps SCORE members could be tapped for expertise. Youth for creativity. Habitat for Humanity.

Equity Particip was a Eugene library book 2+ decades ago, I think Ralph Nader wrote the intro but I cannot find it online.