At one time, I had 72 of these cash flow machines at the same time. But, I never used private lenders. Instead, I would buy subject to the mortgage then wrap the underlying loan when I sold to the owner.
Private lenders can control the deal and I don’t like that. They usually want too high of an interest rate or too short of a term. I prefer the flexibility of buying subject-to a fixed rate low low interest rate loan with NO balloon and NO ARMS. (adjustable rate mortgages).
I do this in Panama now but not in high volume like I did before. Because 90% of the homes in Panama are free and clean ( they hate debt), I buy with seller financing then sell with seller financing. The cash flow is even better because there are no property taxes and insurance is so cheap.