If your using leverage then you're playing a very risky game and just as the upsides are very high, the downsides are equally higher if not more.
Properties that rent 7%+ are very high risk areas where you could easily loose much of the principle. And, you need to look at the percentage return on the total investment after all expenses. After all that, you need to multiply it by .7 because it's considered income.
There are people who this for a living, who know far more about it than anyone else. They run REITS.
I mean, just look at the total returns for REITs. yes, there's some that have dividends as high as 5% up to even 10%, I even have some of them in retirement portfolio but I expect they'll loose some of their principle as any REIT with such a high dividend probably would. Just read any financial review and you'll see that anything with a dividend above 10% is highly suspicious or Risky.
It isn't an efficient market. Efficient markets have very little to no alpha. Real estate has been my best side job ever. Currently looking at a 40% annualized returns since 2015. All thanks to the same principals used to invest in public fixed income and equities.
What exactly is stopping House Flipping BigCo from doing what you're proposing at scale?
Also you need to assess the rental conditions for each property on a case by case basis, and contract everything out to property management.
A lot of REITs invest in medium-large sized complexes to avoid the potential headaches. I’ve lived in a few of these and found them to be quite well managed.