The typical P/HML has a default rate around 1% to 3%.

We are on the edge of mortgage rates getting ready to decline and home values in many states are growing.

I'm sure you will need tools to find deals (eg price/sqft etc), estimate rents, calculate cash-on-cash returns, cap rate etc.

If your goal is to maximize cash flow, look for properties where you can live in one unit and rent the others at market rates.

At the end of 2023 I purchased an old 4plex out of state (MD) for $180k (it appraised for this amount), 20% down with 7.99% rate, mortgage is $1364 with piti.

.: I do not understand doing rehab value adds in cheap markets.  

But even then, seller financing is rarely substantially better than another investment they could make (including trust deed lending, which will often be at a higher rate than seller financing)In my experience, the owners who find owner financing advantageous are at the ends of their careers and are not interested in looking for another investment (other than the usual retirement funding sorts.)

Keep in mind if you buy another primary residence, you'd have better rates, terms and can pay as little as 5% down for multi family up to 4 units.

So the best solution is to buy a house needing extensive renovation for cheap and use that discount to change the layout when you bring it up to living standards. 

Grandpa and Grandma take five acres on the back forty and punch in a well and sewer (when it was cheap to do so), run some water and sewer lines with the old backhoe.