Cash flows will be lumpy.
One year, you are going to have to replace the roof for about $6,000, and if you neglect that there will be another $3k in wood/sheetrock/insulation/paint repairs coming at you. Another year the $1,000 water heater, the $8,000 HVAC, the $4000 sewer line, etc. will go out. This is all if you are lucky and don't have termite, foundation, rotted bathroom floor, or burst water line issues. You can have a profitable year where you handily beat the stock market, but it will be because none of these big expenses happened that particular year. However, within the span of one decade, you will encounter at least half of these items.
To get a realistic long-term rate of return, I suggest switching from cash accounting to accrual accounting. Depreciate the roof, mechanical systems, plumbing systems, and electrical systems, as well as factoring in a bath and kitchen remodel every 25 years or so (less time if it's already old). Arrive at an average ammual cost to provide housing for someone by factoring in the predictable expenses.
Additionally, in my LCOL area, property managers charge 10% AFTER the entire first month's rent. If you can find 8% I'd ask how they can do a good job so cheaply vs. just sitting back and hoping to intercept the occasional rent check. Remember, from the property manager's point of view, their time is better spent getting additional clients rather than hassling tenants for rent or dealing with code enforcement issues, whereas you would hope they'd spend their time taking care of these things. It's a conflict of interest, and a low-baller is almost certainly an absentee PM.
Finally, I would assume one month of vacancy per year (8.4% vacancy rate, not 5%). People rent so they can move from place to place, and even if you get a long-term tenant, the four-month eviction, cleanup, and remod process on the next tenant will put you back on the trend line.
I ran the numbers this way in my LCOL area and roughly matched what I could expect from the stock market - just with a whole lot more work. I hold some REIT preferred stocks that yield over 6% and it's hard for me to sell those to make a down payment on a time-sucking project that might yield 8% if I'm lucky.